miun.sePublications
Change search
Refine search result
1 - 49 of 49
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abdalla, Munir A
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A CMOS APS for dental X-ray imaging using scintillating sensors2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 460, no 1, p. 197-203Article in journal (Refereed)
    Abstract [en]

    In this paper we present an integrating CMOS Active Pixel Sensor (APS) circuit to be used with scintillator type X-ray sensors for intra oral dental X-ray imaging systems. Different pixel architectures were constructed to explore their performance characteristics and to study the feasibility of the development of such systems using the CMOS technology. A prototype 64×80 pixel array has been implemented in a CMOS 0.8 μm double poly n-well process with a pixel pitch of 50 μm. A spectral sensitivity measurement for the different pixels topologies, as well as measured X-ray direct absorption in the different APSs are presented. A measurement of the output signal showed a good linearity over a wide dynamic range. This chip showed that the very low sensitivity of the CMOS APSs to direct X-ray exposure adds a great advantage to the various CMOS advantages over CCD-based imaging systems.

  • 2.
    Abdalla, Munir A
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A new biasing method for CMOS preamplifier-shapers2000In: ICECS 2000: 7TH IEEE INTERNATIONAL CONFERENCE ON ELECTRONICS, CIRCUITS & SYSTEMS, VOLS I AND II, 2000, p. 15-18Conference paper (Refereed)
  • 3.
    Abdalla, Munir A
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    An integrating CMOS APS for X-ray imaging with an in-pixel preamplifier2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 466, no 1, p. 232-236Article in journal (Refereed)
    Abstract [en]

    We present in this paper an integrating CMOS Active Pixel Sensor (APS) circuit coated with scintillator type sensors for intra-oral dental X-ray imaging systems. The photosensing element in the pixel is formed by the p-diffusion on the n-well diode. The advantage of this photosensor is its very low direct absorption of X-rays compared to the other available photosensing elements in the CMOS pixel. The pixel features an integrating capacitor in the feedback loop of a preamplifier of a finite gain in order to increase the optical sensitivity. To verify the effectiveness of this in-pixel preamplification, a prototype 32 x 80 element CMOS active pixel array was implemented in a 0.8 mum CMOS double poly, n-well process with a pixel pitch of 50 mum. Measured results confirmed the improved optical sensitivity performance of the APS. Various measurements on device performance are presented.

  • 4.
    Abdalla, Munir
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Dubaric, Ervin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A scintillator-coated phototransistor pixel sensor with dark current cancellation2001In: cecs2001: 8th IEEE international conference on electronics, circuits and systems, Vols. I-III, Conference Proceedings, 2001, p. 663-667Conference paper (Other academic)
  • 5. Aboelfotoh, M O
    et al.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Schottky-barrier behavior of metals on n- and p-type 6H-SiC2003In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 67, no 7, p. 075312-Article in journal (Refereed)
  • 6.
    Badel, X
    et al.
    KTH.
    Galeckas, A
    Linnros, Jan
    KTH.
    Kleimann, Pascal
    KTH.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Improvement of an X-ray imaging detector based on a scintillating guides screen2002In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 487, no 1-2, p. 129-135Article in journal (Refereed)
  • 7. Badel, X.
    et al.
    Linnros, J.
    Kleimann, P.
    Norlin, Börje
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Koskiahde, E.
    Valpas, K.
    Nenonen, S.
    Petersson, Sture
    Department of Microelectronics, Roy. Inst. of Technology of Sweden, Kista.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Metallized and Oxidized Silicon Macropore Arrays Filled with a Scintillator for CCD-based X-ray Imaging Detectors2004In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 51, no 3 Part 3, p. 1001-1005Article in journal (Refereed)
    Abstract [en]

    Silicon Charge Coupled Devices (CCD)covered with a scintillating film are now available on the market for use in digital medical imaging. However, these devices could still be improved in terms of sensitivity and especially spatial resolution by coating the CCD with an array of scintillating waveguides. In this work, we fabricated such waveguides by first etching pores in silicon, then performing metallization or oxidation of the pore walls and finally filling the pores with CsI(Tl). The resulting structures were observed using SEM and tested under X-ray exposure. The detector performances were also compared with simulations, indicating that the optimal pore depth for metallized macropore arrays is about 80 um while it is around 350 um for oxidized ones. This result, together with the roughness of the metal coating, explains why lower performances were measured experimentally with the metallized macropores. Indeed, our macropore arrays had depths in the range of 210-390 um, which is favorable to oxidized structures.

  • 8.
    Bertilson, Kent
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hjelm, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Monte Carlo Simulation of 4H and 6H-SiC short channel MOSFETs2001In: High Temperature Electronics Network. HITEN ; 4 (Oslo) : 2001.06.05-08: Proceedings of the International Conference on High Temperature Electronics : held in Oslo, Norway, 5th - 8th June 2001, Oxford: Oxford Applied Technology Ltd, , 2001, p. 199-Conference paper (Refereed)
  • 9.
    Bertilsson, Kent
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Dubaric, Ervin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hjelm, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Monte Carlo simulation of vertical MESFETs in 2H, 4H and 6H-SiC2001In: Diamond and related materials, ISSN 0925-9635, E-ISSN 1879-0062, Vol. 10, no 3-7, p. 1283-1286Article in journal (Refereed)
    Abstract [en]

    The 4H-SiC static induction transistor (SIT) is a very competitive device for high frequency and high power applications (3-6 GHz range). The large breakdown voltage and the high thermal conductivity of 4H-SiC allow transistors with extremely high current density at high voltages. The SIT transistor shows better output power capabilities but the unity current-gain frequency is lower compared to a MESFET device. In this work we show, using a very accurate numerical model, that a compromise between the features given by the SIT structure and the ordinary MESFET structure can be obtained using the vertical MESFET structure. The device dimension has been selected very aggressively to demonstrate the performance of an optimized technology. We also present results from drift-diffusion simulations of devices, using transport parameters obtained from the Monte Carlo simulation. The simulations indicate that 2H-SiC is superior to both 4H and 6H-SiC for vertical devices. For lateral devices, 2H-SiC is slightly faster compared to an identical 4H-SiC device

  • 10.
    Bertilsson, Kent
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Dubaric, Ervin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Simulation of a low atmospheric-noise modified four-quadrant position sensitive detector2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 466, no 1, p. 183-187Article in journal (Refereed)
    Abstract [en]

    A modified four-quadrant position sensitive detector (PSD) is developed. This structure is less sensitive to atmospheric turbulence that is a major drawback with the traditional four-quadrant detector. The inter-electrode resistance is as high as for the four-quadrant detector, which is an advantage compared to the lateral effect PSD. The linearity for the modified four-quadrant detector is good in the whole active range of sensing. The structures are limited to small sensing areas with well focused beams and are suitable for use in detectors up to 1 mm in size.

  • 11.
    Bertilsson, Kent
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hjelm, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Käckell, P.
    Persson, C.
    The Effect of Different Transport Models in Simulation of High Frequency 4H-SiC and 6H-SiC Vertical MESFETs2001In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 45, no 5, p. 645-653Article in journal (Refereed)
    Abstract [en]

    A full band Monte Carlo (MC) study of the high frequency performance of a 4H-SiC Short channel vertical MESFET is presented. The MC model used is based on data from a full potential band structure calculation using the local density approximation to the density functional theory. The MC results have been compared with simulations using state of the art drift-diffusion and hydrodynamic transport models. Transport parameters such as mobility, saturation velocity and energy relaxation time are extracted from MC simulations

  • 12.
    Bertilsson, Kent
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Simulation of anisotropic Breakdown in 4H-SiC Diodes2000In: IEEE Workshop on Computers in Power Electronics: COMPEL 2000, IEEE , 2000, p. 118-120Conference paper (Refereed)
    Abstract [en]

    The breakdown characteristics of two-dimensional 4H-SiC diode structures have been studied using an anisotropic drift-diffusion model. The degree of anisotropy was estimated from recent full band Monte Carlo simulations. Identical diode structures have previously been used in the literature to measure the hole impact ionization coefficients of 4H-SiC. The reported measurements from different research groups show large differences in the impact ionization coefficients. Our numerical simulations show that the differences in these measurements can be explained by the difference in device geometry used by the research teams if one considers an anisotropic impact ionization process. This indicates that it is very important to consider anisotropic impact ionization in design and characterization of 4H-SiC power devices.

  • 13. Bocelli, S
    et al.
    Guizzetti, G.
    Marabelli, F.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Experimental identification of the optical phonon of CoSi2 in the infrared1995In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 91, no 1-4, p. 30-33Article in journal (Refereed)
    Abstract [en]

    A weak but clear optical structure was detected at 329 cm−1 by both reflectance and transmittance measurements in the far infrared on a 430 Å film of CoSi2 grown on Si(100). This is the first observation of the IR vibrational mode of the cubic structure of CoSi2 and the result is in very good agreement with theoretical calculations. In order to characterize the sample, the reflectance was extended up to 5.2 × 104 cm−1 and the refractive index was also directly obtained in a more limited spectral range by spectroscopic ellipsometry. The IR structure was then quantitatively analyzed by means of a fit procedure, obtaining the values of ω0 = 327 cm−1 for the phonon energy, of γ = 10.5 cm−1 for the damping parameter and of 0.006 electronic charges for the screened effective ionic charge.

  • 14. Duan, M.
    et al.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Wang, W.
    Linnros, J.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Deposition of Scintillating Layers of Bismuth Germanate (BGO) Films for X-ray detector applications1998In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 45, no 3, p. 525-527Article in journal (Refereed)
    Abstract [en]

    Bi4Ge3O12 films were deposited by pulsed laser ablation on glass and SiO2/Si substrates. The crystal structures of the films depend on the deposition temperature. XRD patterns indicate that the films deposited at substrate temperature less than 400°C are amorphous. The as deposited amorphous films can be crystallized by post rapid thermal annealing (RTA) in the temperature window from 750°C to 800°C for 2 minutes in a oxygen ambient environment. RBS measurements confirm that the films have the same chemical composition as that of the target. The surface morphology of the films were characterized by atomic force microscopy (AFM)

  • 15.
    Dubaric, Ervin
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Resolution and Noise Properties of Scintillator Coated X-ray Detectors2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 466, no 1, p. 178-182Article in journal (Refereed)
    Abstract [en]

    The imaging properties of X-ray pixel detectors depend on the quantum efficiency of X-rays, the generated signal of each X-ray photon and the distribution of the generated signal between pixels. In a scintillator coated device the signal is generated both by X-ray photons captured in the scintillator and by X-ray photons captured directly in the semiconductor. The Signal-to-Noise Ratio in the image is then a function of the number of photons captured in each of these processes and the yield, in terms of electron-hole pairs produced in the semiconductor, of each process. The spatial resolution is primarily determined by the light spreading within the scintillator. In a pure semiconductor detector the signal is generated by one process only. The Signal-to-Noise Ratio in the image is proportional to the number of X-ray photons captured within the sensitive layer. The spatial resolution is affected by the initial charge cloud generated in the semiconductor and any diffusion of carriers between the point of interaction and the readout electrode. In this paper we discuss the theory underlying the imaging properties of scintillator coated X-ray imaging detectors. The model is verified by simulations using MCNP and by experimental results. The results from the two-layer detector are compared with those from a pure semiconductor X-ray detector.

  • 16.
    Dubaric, Ervin
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hjelm, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kackell, P
    The effect of different transport models in simulations of a 4H-SiC ultra short channel MOSFET1999In: Proceedings of International Conference on Microelectronics (ICM'99), 22-24 Nov. 1999 , Kuwait, 1999, p. 247-250Conference paper (Other academic)
  • 17.
    Dubaric, Ervin
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Numerical modelling of the floating body enhanced breakdown in ultra small non-fully depleted SOI MOSFETs1999In: Physica scripta. T, ISSN 0281-1847, Vol. T79, p. 311-313Article in journal (Refereed)
  • 18.
    Fröjdh, Anna
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungstrom, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Frojdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    An optimized system for measurement of radon levels in buildings by spectroscopic measurement of radon progeny2011In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 6, no 12, p. art. no. C12018-Article in journal (Refereed)
    Abstract [en]

    Radon gas, Rn-222, is a problem in many buildings. The radon gas is not harmful in itself, but the decay chain contains charged elements such as Po-218, and Po-214 ions which have a tendency to stick to the lungs when inhaled. Alpha particles from the decay of these ions cause damages to the lungs and increase the risk of lung cancer. The recent reduction in the limits for radon levels in buildings call for new simple and efficient measurement tools [1]. The system has been optimized through modifications of the detector size, changes to the filters and the design of the chamber. These changes increase the electric field in the chamber and the detection efficiency.

  • 19.
    Fröjdh, Anna
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    An alpha particle detector for measuring radon levels2010In: Proceedings of Nuclear Science Symposium Conference Record (NSS/MIC), 2010, IEEE conference proceedings, 2010, p. 460-461Conference paper (Refereed)
    Abstract [en]

    An alpha particle detector for measuring radon levels through measurement of radon progeny concentration has been developed. The detector is a silicon diode optimized for these measurements. Different alternating and non-alternating guard ring structures and different doping profiles have been investigated.

  • 20.
    Fröjdh, Anna
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Measurement of radon levels in buildings by spectroscopic measurement of radon progeny2010In: Proceedings of Nuclear Science Symposium Conference Record (NSS/MIC), 2010, IEEE conference proceedings, 2010, p. 1229-1231Conference paper (Refereed)
  • 21.
    Fröjdh, Christer
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Andersson, J
    Bates , R
    Heuken, M
    Irsigler, R
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    O'Shea, V
    Smith, K M
    Stamatakis, H
    Welander, U
    New sensors for dental X-ray imaging1999In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 434, no 1, p. 24-29Article in journal (Refereed)
  • 22.
    Fröjdh, Christer
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nelvig, P.
    Simulation of the X-ray Response of Scintillator Coated Silicon CCDs1998In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 45, no 3, Pt 1, p. 374-378Article in journal (Refereed)
  • 23.
    Fröjdh, Christer
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hatzikonstantinidou, S.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Processing and characterisation of an etched groove Permeable1994In: Physica scripta. T, ISSN 0281-1847, Vol. T54, p. 56-59Article in journal (Refereed)
    Abstract [en]

    The Permeable Base Transistor (PBT) is generally considered as an interesting device for high speed applications. PBTs have been fabricated on Silicon and Gallium Arsenide by a number of groups. In this paper we reported on the fabrication of an etched groove PBT structure on 6H-SiC using Ti as contact metal for all electrodes. The devices have been characterised by DC-measurements. The transistors show the normal IV-characteristics for a such a device except for a parasitic series diode at the drain electrode. The breakdown voltage of the gate-drain diode is generally as high as around 60 V even without passivation of the sidewalls of the grooves.

  • 24.
    Fröjdh, Christer
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Schottky Barriers on 6H-SiC1999In: Physica scripta. T, ISSN 0281-1847, Vol. T79, p. 297-302Article in journal (Refereed)
    Abstract [en]

    Schottky diodes have been fabricated by deposition of Ti, Ni, Cu on epitaxial layers of p-type and n-type 6H-SiC. The fabricated devices have been characterised by CV, IV and photoelectric measurements. The results from the different characterisations are compared. The effect of incomplete ionisation of dopants and high series resistance on the results from CV-measurements is discussed.

    In addition to the results obtained from the experiments presented in this paper data has also been collected from other research groups in order to investigate the mechanism of Schottky barrier formation on Silicon Carbide. The results show that for a number of metals the barrier height is strongly correlated to the difference between the electron affinity of the semiconductor and the metal work function, while other metals show significant deviation from the Schottky-Mott theory.

  • 25.
    Fröjdh, Christer
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    UV-sensitive metal-semiconductor photodiodes on 6H-SiC1994In: Proceedings of the 1994 MRS Spring Meeting, 1994, p. 215-220Conference paper (Other scientific)
  • 26.
    Fröjdh, Christer
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    UV-sensitive photodetectors based on metal-semiconductor contacts on 6H-SiC1994In: Physica scripta. T, ISSN 0281-1847, Vol. T54, p. 169-171Article in journal (Refereed)
  • 27. Hatzikonstantinidou, S.
    et al.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Process Optimisation and Characterisation of PBT structures1994In: Physica scripta. T, ISSN 0281-1847, Vol. T54, p. 226-229Article in journal (Refereed)
    Abstract [en]

    The Permeable Base Transistor (PBT) is considered to be a high frequency device with simulated fT and fmax values in the order of 100 GHz. In this work we present several PBT devices in silicon. The fabrication process steps have been developed and optimised in order to meet the demands of a future integration in a standard CMOS processing. Cobalt disilicide is used for the emitter metallization and base metallisation in order to form a good Schottky contact. The important issues of a fabrication process reliability and controllability are discussed in this paper. The process steps had been analysed by standard analysis methods. Electrical (DC) characterisation of the devices has been performed. The obtained results are in a good agreement with the 2D simulations.

  • 28.
    Hjelm, Mats
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Dubaric, Ervin
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Kackell, P
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Full band Monte Carlo simulation of a 100 nm 4H-SiC high frequency MOSFET1998In: Compound Semiconductors 1998. Proceedings of the Twenty-Fifth International Symposium on Compound Semiconductors 12-16 Oct. 1998 , Nara, Japan, 1998, p. 273-278Conference paper (Other academic)
  • 29.
    Kleimann, P
    et al.
    KTH.
    Linnros, J
    KTH.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    An x-ray imaging pixel detector based on a scintillating guides screen2000In: IEEE Transactions on Nuclear Science, ISSN 0018-9499, E-ISSN 1558-1578, Vol. 47, no 4, p. 1483-1486Article in journal (Refereed)
  • 30.
    Kleimann, Pascal
    et al.
    KTH.
    Linnros, Jan
    KTH.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    An X-ray imaging pixel detector based on scintillator filled pores in a silicon matrix2001In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 460, no 1, p. 15-19Article in journal (Refereed)
  • 31.
    Kok, A.
    et al.
    SINTEF ICT, Dept Microsyst & Nanotechnol, Oslo, Norway.
    Kohout, Z.
    Czech Tech Univ, Inst Expt & Appl Phys, Prague 12800, Czech Republic.
    Hansen, T. -E
    SINTEF ICT, Dept Microsyst & Nanotechnol, Oslo, Norway.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design. Czech Tech Univ, Inst Expt & Appl Phys, Prague 12800, Czech Republic.
    Pospisil, S.
    Czech Tech Univ, Inst Expt & Appl Phys, Prague 12800, Czech Republic.
    Rokne, J.
    Oslo & Akershus Univ, Coll Appl Sci, Dept Ind Dev, Oslo, Norway.
    Slavicek, T.
    Czech Tech Univ, Inst Expt & Appl Phys, Prague 12800, Czech Republic.
    Soligard, S.
    Oslo & Akershus Univ, Coll Appl Sci, Dept Ind Dev, Oslo, Norway.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Vykydal, Z.
    Czech Tech Univ, Inst Expt & Appl Phys, Prague 12800, Czech Republic.
    Silicon sensors with pyramidal structures for neutron imaging2014In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 9, p. Art. no. C04011-Article in journal (Refereed)
    Abstract [en]

    Neutron detection is a valuable tool in nuclear science research, homeland security, quality assurance in nuclear plants and medical applications. Recent developments and near future instrumentations in neutron imaging have a need for sensors with high spatial resolution, dynamic range, sensitivity and background discrimination. Silicon based neutron detectors can potentially fulfil these requirements. In this work, pad and pixel detectors with pyramidal micro-structures have been successfully fabricated that should have an improved detection efficiency when compared to conventional planar devices. Titanium di-boride (TiB2) and lithium fluoride (LiF) were deposited as the neutron converters. Excellent electrical performances were measured on both simple pad and pixel detectors. A selection of pad detectors was examined by alpha spectroscopy. Measurement with thermal neutrons from a 241Am-Be source shows an improvement in relative efficiency of up to 38% when compared to conventional planar devices.

  • 32.
    Krapohl, David
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Nilsson, Hans-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Pospisil, S
    Institute of Experimental and Applied Physics (IEAP), Czech Technical University, Horskà 3a/22, 128 00 Prague 2, Czech Republic.
    Slavicek, Tomas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Simulation of a silicon neutron detector coated with TiB 2 absorber2012In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 7, no 1, p. Art. no. C01096-Article in journal (Refereed)
    Abstract [en]

    Neutron radiation cannot be directly detected in semiconductor detectors and therefore needs converter layers. Planar clean-room processing can be used in the manufacturing process of semiconductor detectors with metal layers to produce a cost-effective device. We used the Geant4 Monte-Carlo toolkit to simulate the performance of a semiconductor neutron detector. A silicon photo-diode was coated with vapour deposited titanium, aluminium thin films and a titaniumdiboride (TiB 2) neutron absorber layer. The neutron capture reaction 10B(n, alpha)7Li is taken advantage of to create charged particles that can be counted. Boron-10 has a natural abundance of about SI 19.8%. The emitted alpha particles are absorbed in the underlying silicon detector. We varied the thickness of the converter layer and ran the simulation with a thermal neutron source in order to find the best efficiency of the TiB 2 converter layer and optimize the clean room process. © 2012 IOP Publishing Ltd and SISSA.

  • 33. Ljungberg, K.
    et al.
    Söderberg, A.
    Tiensuu, A-L
    Johansson, S.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Buried Cobalt Silicide Layers in Silicon Created by Wafer Bonding1994In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 141, no 10, p. 2829-2833Article in journal (Refereed)
    Abstract [en]

    A buried conductive layer in silicon has been created using wafer bonding technique, with a cobalt interfacial layer.Co-coated silicon wafers were brought into contact with either similar or uncoated wafers at room temperature. CoSi2 wasthen formed through a solid-phase reaction, during an anneal at 700 to 900°C. A 700 Å buried CoSi2-layer, with a resistivityof approximately 21 µ cm, was achieved. Good adhesion, as measured by tensile strength testing, between the wafers wasachieved. Transmission electron microscopic investigations (Co-coated wafer bonded to bare silicon) showed that thesilicide has not grown into the opposite wafer, and that an amorphous layer exists between the silicide and the siliconsurface. The presence of such a layer has been confirmed by electrical characterization.

  • 34.
    Nilsson, Hans-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Andersson, T.
    Sannemo, Ulf
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    An Investigation of the blocking characteristics of the Permeable Base Transistor1998In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 42, no 3, p. 297-305Article in journal (Refereed)
    Abstract [en]

    A numerical study of the blocking characteristics of the Permeable Base Transistor (PBT) is presented. The PBT is regarded as a promising transistor structure for high voltage and high frequency applications. Numerical studies of the PBT were focused on the high frequency figure of merits or the breakdown characteristics of the Schottky gate. A device designed for high frequency and high voltage switching should be optimized for large blocking and fast switching. The trade off between blocking and speed is a complicated matter which depends strongly on the geometry and doping level. In this work we studied the blocking characteristics for a Silicon PBT with regard to the doping level and doping profile, gate thickness and gate to drain distance. A scaling formalism was developed in order to estimate the transistor performance for a wide range of doping levels and geometrical combinations. A design example is presented of a normally off transistor that can block a drain to source voltage of 10 V while the unity current gain frequency fT value for Vgs = 0.2 V is higher than 7 GHz.

  • 35.
    Nilsson, Hans-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Hjelm, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Persson, Clas
    Sannemo, Ulf
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Full band Monte Carlo simulation of electron transport in 6H-SiC1999In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 86, no 2, p. 965-973Article in journal (Refereed)
  • 36.
    Nilsson, Hans-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sannemo, U.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Monte carlo simulation of electron transport in 4H-SiC using a two band model with multiple minima1996In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 80, no 6, p. 3365-3369Article in journal (Refereed)
  • 37.
    Nilsson, Hans-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sannemo, Ulf
    Koel, A.
    Masszi, F.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    The effect of using different transport models in computer simulations of the permeable-base transistor1994In: Physica Scripta Volume T, ISSN 0281-1847, Vol. T54, p. 141-145Article in journal (Refereed)
  • 38.
    Nilsson, Hans-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sannemo, Ulf
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A semi-analytic model of the Permeable Base Transistor1994In: Physica scripta. T, ISSN 0281-1847, Vol. T54, p. 159-164Article in journal (Refereed)
    Abstract [en]

    The I-V characteristics of the Permeable Base Transistor (PBT) has been investigated in order to find a simple and practical model for use in circuit designs. Two possible approaches has been discussed, a one-dimensional analytical solution and a semi-analytical solution mixing analytical and empirical methods. The semi-analytical model developed in this paper offers high accuracy and a simple and fast evaluation. All model parameters can be extracted from a set of I-V curves from two typical transistors with different threshold voltages. An analytical small signal model has been developed that agrees very well with two-dimensional simulations.

  • 39.
    Nilsson, Hans-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sannemo, Ulf
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Different methods of noise reduction in Monte Carlo simulations of a Schottky diode1994In: Physica scripta. T, ISSN 0281-1847, Vol. T54, p. 268-272Article in journal (Refereed)
    Abstract [en]

    Methods of decreasing the noise and increasing the computational efficiency in Monte Carlo simulations of semiconductor devices are investigated. A lookup table approach to the charge assignment to mesh points has been implemented which is independent of the complexity of the assignment function. Using this approach reduces the CPU time of the charge assignment to about one third. Potential fluctuations in low field regions are compared for different assignment function, which shows the advantage of using more complex schemes than those generally used. Results from a full band Monte Carlo simulation of a submicron Schottky diode are presented and the values of the current density for different assignment schemes are compared, showing a lower noise for the higher order schemes. Statistical enhancements by splitting of superparticles in the depletion region has been investigated. The combination of a high order assignment scheme and statistical enhancement by splitting decreases simulation runtimes considerable for a given noise tolerance.

  • 40.
    Nilsson, Hans-Erik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sannemo, Ulf
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Investigation of hot carrier transport in silicon Permeable Base Transistors1996In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 43, no 6, p. 924-931Article in journal (Refereed)
  • 41.
    Petersson, Sture
    et al.
    Uppsala Universitet.
    Norde, Herman
    Uppsala Universitet.
    Possnert, G
    Uppsala Universitet.
    Orre, B
    Uppsala Universitet.
    Oxygen distribution profiles in thin evaporated contacts on single crystal silicon1978In: Nuclear instruments and methods, Vol. 149, p. 285-288Article in journal (Refereed)
    Abstract [en]

    The nuclear resonance in the l6O(a, a)l6O elastic scattering reaction at 3.045 MeV has been used in concentration profilemeasurements ol oxygen in thin-film structuresThe concentration profile can be deduced lrom an energy scan ol the incoming a-particies, thus shifting the resonanceto different depths in the sample. The methocl has been applie<i to studies of the structures (a) an etched Si-surface, (b)Au evaporated on Si, and (c) a Au-Ge-Si structure. Eviclence is presented for the presence of oxygen in the Au layerand in the Ge layer.

  • 42.
    Possnert, G
    et al.
    Uppsala Universitet.
    Fahlander, C
    Uppsala Universitet.
    Orre, B
    Uppsala Universitet.
    Norde, H
    Uppsala Universitet.
    Petersson, Sture
    Uppsala Universitet.
    Tove, P. A.
    Uppsala Universitet.
    Oxygen content and depth profiling in silicon surface technology studied by the 16O(α, α)16O resonance at 3.045 MeV1978In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 18, p. 353-356Article in journal (Refereed)
    Abstract [en]

    The use of the t6O(o,o)160 elastic scattering resonance reaction forthe study of low concentration of oxygen such as found in interfacesin silicon technology is described. We have investigated the depth resolution and the limit of the sensitivity that can be obtained with thismethod. The method has been applied to the study of AlrQ{r "sandwich" film structures and to Au and amorphous Ge contacts to silicon.

  • 43.
    Slavicek, Tomas
    et al.
    Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 128 00 Praha, Czech Republic.
    Kralik, M
    Czech Metrology Institute, Radiová 1, 102 00 Praha 10, Czech Republic.
    Krapohl, David
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Pospisil, S
    Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, 128 00 Praha, Czech Republic.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A thermal neutron detector based on planar silicon sensor with TiB 2 coating2012In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 7, no 1, p. Art. no. C01053-Article in journal (Refereed)
    Abstract [en]

    Neutron radiation as a non-ionizing radiation is particularly difficult to detect; therefore a conversion material is required. The conversion material converts neutrons into secondary charged particles in order for them to be detected in a silicon detector. The use of titanium diboride (TiB 2) as the conversion material deposited by an electron beam-physical vapour deposition (EB-PVD) as a part of a front-side contact of a planar silicon detector is presented. The effect of different front-side contact material compositions is discussed. The detectors behaviour was examined using alpha particles and thermal neutrons from an 241Am-Be source. Simultaneously, a Geant4 simulation was so as executed to evaluate the conversion layer functionality and to discover the conversion material thickness for the best neutron detection efficiency. © 2012 IOP Publishing Ltd and SISSA.

  • 44.
    Thungström, Göran
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Buried Schottky Contacts in Patterned Cobalt Silicide Layers in Silicon Using Wafer Bonding1994In: Proceedings of the MRS Symposium, 1994, p. 475-480Conference paper (Other academic)
  • 45.
    Thungström, Göran
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Svedberg, P.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Contacts to Monocrystalline N- and P-type Silicon by Wafer Bonding Using1994In: Physica scripta. T, ISSN 0281-1847, Vol. T54, p. 77-80Article in journal (Refereed)
    Abstract [en]

    Contacts to monocrystalline silicon have been prepared by wafer bonding using cobalt disilicide as an interfacial layer. Bonding has been carried out with three different structures: n+ -CoSi2-n+, p+ -CoSi2-p+ and p+ -CoSi2-n+. The intermediate cobalt disilicide layers had a thickness of either 700 Å or 5250 Å. The bonding interface was characterized by electrical measurement (IV) and Secondary-ion mass spectrometry (SIMS) of the formed contacts. The n+ -CoSi2-n+ and p+ -CoSi2-p+ bondings display an ohmic behaviour. The resistance of the bonded structures was in the range expected for the bulk silicon used (0.1-0.05 Ω cm). The p+ -CoSi2-n+ structures shows a non ohmic behaviour. An evaluation of the SIMS profiles reveals that the non-linear behaviour of the p+ -CoSi2-interface is due to phosphorous diffusion from the n-doped region across the silicide to the p-doped area. It is shown that the phosphorous compensates the boron dopant.

  • 46.
    Thungström, Göran
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Westerberg, Lars
    Spohr, Reimar
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fabrication and Characterization of thin delta E-Detectors for Spectroscopic Application2005In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 546, no 1-2, p. 312-318Article in journal (Refereed)
    Abstract [en]

    Ultra thin delta E-detectors for spectroscopic applications have been fabricated and characterized down to a thickness of 4.5 μm. A common one-side mask aligner was in use to fabricate the detectors. The detectors display low leakage current and the resulting capacitance is close to the detector window capacitance below a threshold voltage. The detector telescope should be slightly tilted to reduce the probability for channeling. However, even better control of the thickness uniformity is needed to improve the resolution in the E-E detector telescope

  • 47. Uher, J
    et al.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Holy, T
    Jakubek, J
    Pettersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Pospsisil, S
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Silicon detectors for neutron imaging2007In: NUCLEAR PHYSICS METHODS AND ACCELERATORS IN BIOLOGY AND MEDICINE: Fourth International Summer School on Nuclear Physics Methods and Accelerators in Biology and Medicine., American Institute of Physics (AIP), 2007, Vol. 958, no 1, p. 101-104Conference paper (Refereed)
    Abstract [en]

    Semiconductor silicon detectors are used in many applications for detection and imaging of ionizing radiation. Detection of neutrons is also possible with these devices. However, the silicon detectors must be adapted for the thermal neutron detection and imaging. The devices must be supplemented with a material which ``converts'' neutrons into a radiation detectable directly in the semiconductor detector. The principle of the thermal neutron detection with semiconductor silicon detectors is explained. Advantages of such detectors are shown as well as their limitations. The way of the detector improvement using 3D detector technologies is described. The 3D detector properties were simulated; real 3D structures were fabricated and successfully tested with a beam of thermal neutrons, finally. The functionality of these devices was proved.

  • 48.
    Uher, J.
    et al.
    Czech Technical University in Prague, Czech Republic.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Jakubek, J.
    Czech Technical University in Prague, Czech Republic.
    Kenney, C.
    Stanford University, United States.
    Kohout, Z.
    Czech Technical University in Prague, Czech Republic.
    Linhart, V.
    Czech Technical University in Prague, Czech Republic.
    Parker, S.
    University of Hawaii, United States.
    Petersson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Pospisil, S.
    Czech Technical University in Prague, Czech Republic.
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Characterization of 3D thermal neutron semiconductor detectors2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 576, no 1, p. 32-37Article in journal (Refereed)
    Abstract [en]

    Neutron semiconductor detectors for neutron counting and neutron radiography have an increasing importance. Simple silicon neutron detectors are combination of a planar diode with a layer of an appropriate neutron converter such as (LiF)-Li-6. These devices have limited detection efficiency of not more than 5%. The detection efficiency can be increased by creating a 3D microstructure of dips, trenches or pores in the detector and filling it with a neutron converter. The first results related to the development of such devices are presented. Silicon detectors were fabricated with pyramidal dips on the surface covered with (LiF)-Li-6 and then irradiated by thermal neutrons. Pulse height spectra of the energy deposited in the sensitive volume were compared with simulations. The detection efficiency of these devices was about 6.3%. Samples with different column sizes were fabricated to study the electrical properties of 3D structures. Charge collection efficiencies in silicon columns from 10 to 800 mu m wide and 80-200 mu m high were measured with alpha particles.

    The neutron detection efficiency of a full 3D structure was simulated. The results indicate an increase in detection efficiency by a factor of 6 in comparison with a standard planar neutron detector.

  • 49. Uher, J
    et al.
    Fröjdh, Christer
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Jakubek, J
    Kenney, C
    Kohout, Z
    Linhart, V
    Parker, S
    Petterson, Sture
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Pospisil, S
    Thungström, Göran
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Highly sensitive silicon detectors of thermal neutrons2007In: Nuclear Science Symposium Conference Record, 2006. IEEE. Vol 3., IEEE conference proceedings, 2007, Vol. 3, p. 1346-1348Conference paper (Refereed)
    Abstract [en]

    Planar semiconductor diodes supplemented with a layer of an appropriate neutron converter such as 6LiF can be used for thermal neutron counting or imaging. Neutrons interacting in the converter generate alphas and tritons which enter the semiconductor and are detected there. However, simple planar devices suffer from limited detection efficiency which cannot reach more than about 5%. The limit in detection efficiency can be overcome by etching a 3D microstructure of trenches, pores or columns in the detector and filling it with the neutron converter. The overall neutron detection efficiency of such structure with pores was simulated. The results indicate an increase in the detection efficiency by factor of 6 in comparison with a standard planar neutron detector. Samples with different silicon column sizes were fabricated to study the electrical properties of 3D structures. The charge collection efficiency in silicon columns from 10 μm to 800 μm wide and 80 μm high was measured. Single pad detectors with pores were also fabricated and tested for thermal neutron detection. The samples have square pores of 20 μm wide, ~60 μm deep. The pore pitch is 70 μm. 6LiF was used as the neutron converter in all cases. Pulse height spectra of the filled samples irradiated by thermal neutrons were measured. The measurement proved functionality of such detectors and its usability for thermal neutron detection.

1 - 49 of 49
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf