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  • 1.
    Andersson, Henrik
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Lundgren, Anders
    SiTek Electro Optics.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    The effect of mechanical stress on lateral-effect position sensitive detector characteristics2006Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 563, nr 1, s. 150-154Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Position-sensitive detectors (PSDs) are widely used in noncontact measurement systems. In order to minimize the size of such systems, interest has increased in mounting the PSD chip directly onto printed circuit boards (PCBs). Stress may be induced in the PSD because of the large differences in thermal expansion coefficients, as well as the long-term geometrical stability of the chip packaging. Mechanical stress has previously been shown to have an effect on the performance of semiconductors. The accuracy, or linearity, of a lateral effect PSD is largely dependent on the homogeneity of the resistive layer. Variations of the resistivity over the active area of the PSD will result in an uneven distribution of photo-generated current, and hence an error in the readout position. In this work experiments were performed to investigate the influence of anisotropic mechanical stress in terms of nonlinearity. PSD chips of 60×3 mm active area were subjected, respectively, to different amounts of compressive and tensile stress to determine the influence on the linearity.

  • 2.
    Ashraf, Shakeel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Forsberg, Viviane
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap. KTH, Wallenberg Wood Science Center, Stockholm.
    Mattsson, Claes G.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Thermoelectric properties of n-type molybdenum disulfide (MoS2) thin film by using a simple measurement method2019Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, nr 21, artikel-id 3521Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a micrometre thin film of molybdenum disulfide (MoS2) is characterized for thermoelectric properties. The sample was prepared through mechanical exfoliation of a molybdenite crystal. The Seebeck coefficient measurement was performed by generating a temperature gradient across the sample and recording the induced electrical voltage, and for this purpose a simple measurement setup was developed. In the measurement, platinum was utilized as reference material in the electrodes. The Seebeck value of MoS2 was estimated to be approximately -600 μV/K at a temperature difference of 40 °C. The negative sign indicates that the polarity of the material is n-type. For measurement of the thermal conductivity, the sample was sandwiched between the heat source and the heat sink, and a steady-state power of 1.42Wwas provided while monitoring the temperature difference across the sample. Based on Fourier's law of conduction, the thermal conductivity of the sample was estimated to be approximately 0.26 Wm-1 K-. The electrical resistivity was estimated to be 29 W cm. The figure of merit of MoS2 was estimated to be 1.99 × 10-4. 

  • 3.
    Ashraf, Shakeel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Fondell, Mattis
    Helmholtz Zentrum, Inst Methods & Instrumentat Synchrotron Radiat Re, Berlin, Germany.
    Lindblad, Andreas
    Uppsala Univ, Dept Chem, Angstrom Lab, Uppsala, Sweden.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Surface modification of SU-8 for metal/SU-8 adhesion using RF plasma treatment for application in thermopile detectors2015Ingår i: Materials Research Express, ISSN 2053-1591, Vol. 2, nr 8, artikel-id 086501Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article reports on plasma treatment of SU-8 epoxy in order to enhance adhesive strength for metals. Its samples were fabricated on standard silicon wafers and treated with (O2 & Ar) RF plasma at a power of 25W at a low pressure of (3×10-3 torr) for different time spans (10 sec – 70 sec). The sample surfaces were characterized in terms of contact angle, surface (roughness and chemistry) and using a tape test. During the contact angle measurement, it was observed that the contact angle was reduced from 73° to 5° (almost wet) and 23° for (O2 & Ar) treated samples, respectively. The RMS surface roughness was significantly increased by 21.5% and 37.2% for (O2 & Ar) treatment, respectively. A pattern of metal squares was formed on the samples using photolithography for a tape test. An adhesive tape was applied to the samples and peeled off at 180o. The maximum adhesion results, more than 90%, were achieved for the O2-treated samples, whereas the Ar-treated samples showed no change. The XPS study shows the formation of new species in the O2-treated sample compared to the Ar-treated samples. The high adhesive results were due to the formation of hydrophilic groups and new O2 species in the O2-treated samples, which were absent in Ar-treated samples.

  • 4.
    Ashraf, Shakeel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Fabrication and characterization of a SU8-epoxy membrane based thermopile detector with an integrated multilayered absorber structure for the mid-IR region2019Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 19, nr 11, s. 4000-4007Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports on the fabrication and characterization of a thermopile detector with an integrated mid-infrared absorber structure. The fabricated absorber structure has shown an absorption of more than 95% in the wavelength range of 3.2 – 5.47 μm. The detector was fabricated with standard cleanroom process techniques and equipment. The serial resistance was measured at about 315 kΩ at room temperature. The photosensitivity of the detector was characterized for a signle wavelength (4.26 µm) and a band of wavelength ranging from 2.5 –5.5 µm through two different measurement setups. In the first measurement setup, the photosensitivity was estimated at 57.5 V·mm2·W-1 through a MEMS-based infrared radiation source and with an optical band-pass filter of wavelength 4.26µm. The following characterization was performed to characterise the photosensitivity of the detector in a broader wavelength range. This measurement was taken using a monochromator setup utilizing a reference photodetector for calculations of the optical power of the infrared source. The photosensitivity and the specific detectivity (D*) of the fabricated detector were measured to values of 30-92 V·W-1 and 8.0×107-2.4×108 cm·Hz1/2·W-1, respectively, in the wavelength range of 2.8 – 5 µm. The time constant was estimated to around 21 ms

  • 5.
    Ashraf, Shakeel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Fabrication of a mid-Ir sensitive thermopile detector2016Ingår i: Proceedings of IEEE Sensors, IEEE, 2016, artikel-id 7808481Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports on the integration of a multilayered mid-infrared absorber structure into a SU-8 epoxy membrane-based thermopile detector. The absorber structure was designed and simulated using transfer matrix theory. The fabricated absorber structures were characterized through Fourier transform infrared spectroscopy. The structure shows an absorption of more than 95% in the wavelength range of 3.30pm–5pm for simulations, and 3.2pm–5.47pm for FTIR measurements. The complete fabrication process of a thermopile detector including the integration of a multilayered absorber structure has been presented. A MEMS based infrared emitter was used to characterize the fabricated detector. The serial resistance was measured to 315 kΩ and the responsivity was calculated to 57.5 Vmm2W−1 at a wavelength of 4.26pm. The time constant for the fabricated detector was estimated to around 21ms.

  • 6.
    Ashraf, Shakeel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Gaynullin, B.
    Research and Development Department, SenseAir AB, Delsbo.
    Rödjegård, H.
    Research and Development Department, SenseAir AB, Delsbo.
    Evaluation of a CO2 sensitive thermopile with an integrated multilayered infrared absorber by using a long path length NDIR platform2018Ingår i: I2MTC 2018 - 2018 IEEE International Instrumentation and Measurement Technology Conference: Discovering New Horizons in Instrumentation and Measurement, Proceedings, IEEE, 2018, s. 1-6Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this work, a mid-infrared-sensitive thermopile detector was evaluated for carbon dioxide gas. The thermopile has an integrated absorber structure that has more than 95% absorption for the wavelength range of 3.3-5.5 μm. For the measurement of carbon dioxide, the detector was initially assembled on a small printed circuit board holder and then installed in a long path length non-dispersive infrared platform. The measurement setup was calibrated by exposing the detector to carbon dioxide of known concentrations (from 50 ppm to 1,300 ppm) and measuring the corresponding voltage response of the detector. The measured voltage values allowed us to calculate the calibration constant for this detector. This was followed by a verification process using a concentration of 500 ppm (which was not used in the calibration) and a known value of 1,300 ppm. The verification results matched with real values, demonstrating that the sensor can be used for highly sensitive and accurate carbon dioxide measurements at concentrations from a few ppm level up to 1,300 ppm. Above this level, additional calibration is needed. 

  • 7.
    Ashraf, Shakeel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Rödjegard, Henrik
    Design of a multilayered absorber structure based on SU-8 epoxy for broad and efficient absorption inMid-IR sensitive thermal detectors2014Ingår i: Proceedings, 2014, s. 938-941Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports on design, simulation and fabrication of a multilayered interferometric absorption structure with a broad absorption in the mid-infrared band. This region is used for IR based CH4 and CO2 detection. The structure consists of five layers of different thickness. The structure consists of one mirror layer of aluminium, two SU-8 epoxy layers and two thin titanium layers. This structure has been fabricated on a silicon substrate and verified for its absorption properties through Fourier transform infrared spectroscopy. The fabricated structure has been compared with simulations are performed using transfer matrix theory. The structure shows more than 90% absorption in the wavelength range of 3.20μm - 5.35μm for simulations and 3.13μm - 5.47μm for FT-IR measurements. The transmission and reflection of SU-8 epoxy was measured using FT-IR (that), resulting in a calculated absorption between 10 - 20% in the area of interest (3μm - 6μm). The use of SU-8 epoxy as dielectric medium, allows for direct integration of the structure into the membrane of a SU-8 membrane based thermopile. The integration results in minimum increase of the thermal capacitance and conductance, which results in maximum detector sensitivity and minimum time constant.

  • 8.
    Ashraf, Shakeel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Rödjegard, Henrik
    SenseAir AB, Delsbo, Sweden.
    Integration of an interferometric IR absorber into an epoxy membrane based CO2 detector2014Ingår i: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 9, nr 5, s. Art. no. C05035-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measurements of carbon dioxide levels in the environment are commonly performedby using non-dispersive infrared technology (NDIR). Thermopile detectors are often used in NDIRsystems because of their non-cooling advantages. The infrared absorber has a major influence onthe detector responsivity. In this paper, the fabrication of a SU-8 epoxy membrane based Al/Bithermopile detector and the integration of an interferometric infrared absorber structure of wavelength around 4 µ m into the detector is reported. The membrane of thermopile detector has beenutilized as a dielectric medium in an interferometric absorption structure. By doing so, a reduction in both thermal conductance and capacitance is achieved. In the fabrication of the thermopile,metal evaporation and lift off process had been used for the deposition of serially interconnectedAl/Bi thermocouples. Serial resistance of fabricated thermopile was measured as 220 kΩ. Theresponse of fabricated thermopile detector was measured using a visible to infrared source of radiation flux 3.23 mW mm−2. The radiation incident on the detector was limited using a band passfilter of wavelength 4.26 µ m in front of the detector. A responsivity of 27.86 V mm2W−1at roomtemperature was achieved using this setup. The fabricated detector was compared to a referencedetector with a broad band absorber. From the comparison it was concluded that the integratedinterferometric absorber is functioning correctly.

  • 9.
    Ashraf, Shakeel
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Niskanen, Ilpo
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion. University of Oulu, Finland.
    Kanyathare, Boniphace
    Electronics and Telecommunications Department, Dar es salaam Institute of Technology, Tanzania.
    Vartiainen, Erik
    LUT School of Engineering Science, Lappeenranta University of Technology, Finland.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Heikkilä, Rauno
    Faculty of Technology, Structures and Construction Technology, University of Oulu, Finland.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Determination of complex refractive index of SU-8 by Kramers-Kronig dispersion relation method at the wavelength range 2.5 – 22.0 μm2019Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 224, s. 309-311Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accurate determination of the complex refractive index of SU-8 epoxy has significant for the wide variety of applications in optical sensor technology at IR range. The complex refractive index of SU-8 is determined by recording the transmission of light spectra for the wavelength range of 2.5 – 22.0 μm.  The data analysis is based on the Kramers-Kronig dispersion relation method. The method has several merits, such as ease of operation, non-contact technique, measurement accuracy, and rapid measurement. The present method is not restricted to the case of SU-8 but it is also proposed to be applicable across a broad range of applications, such as assessment of the optical properties of paints and biomedical samples.

  • 10.
    Gaynullin, Bakhram
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion. SenseAir AB.
    Bryzgalov, M
    SenseAir AB.
    Hummelgård, Christine
    SenseAir AB.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Rödjegård, Henrik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion. SenseAir AB.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Pressure characterization and resolution limits' investigation of high accuracy NDIR Methane sensor for environmental applications2017Konferensbidrag (Refereegranskat)
  • 11.
    Gaynullin, Bakhram
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion. SenseAir AB.
    Hummelgård, Christine
    SenseAir AB.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Rödjegård, Henrik
    SenseAir AB.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Comparative study of CO2 and CH4 pressure dependence in the HPP NDIR platform2015Konferensbidrag (Övrigt vetenskapligt)
  • 12.
    Gaynullin, Bakhram
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion. Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion. Engineer.
    Hummelgård, Christine
    Rödjegård, Henrik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för elektronikkonstruktion. Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier (-2013). Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap, teknik och matematik (-2012). Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för elektronikkonstruktion.
    Efficient pressure compensation of low-cost NDIR sensors for environmental studiesIngår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using commercial low-cost NDIR gas sensors for atmospheric measurements requires pressure compensation for an accurate readout; this is normally not implemented. Herein, we present an efficient pressure compensation method. This includes a lab test system for studying pressure dependence in accuracy-demanding applications to introduce interpolation in the concentration dimension. A two-dimensional algorithm allows compensation in the entire pressure-concentration space using a minimum of data. The obtained compensation parameters are used for the recalculation of the measured concentrations to true molar fractions valid for standard atmospheric pressure.

  • 13.
    Lars, Herrnsdorf
    et al.
    RTI electronics.
    Björk, M
    RTI electronics.
    Cederquist, Björn
    RTI electronics.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Fröjdh, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Point Dose Profile Measurments using Solid State Detectors in Characterization of Computed Tomograhy Systems2009Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 607, nr 1, s. 223-225Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Existing solid-state detectors for point dose measurements are typically mounted in a package with a high Z material acting as the back contact causing unsymmetrical response. In the Computed Tomography (CT) dose profile application this is a major drawback. A new silicon detector has been constructed without this disturbing element. The new detector has been mounted in a cylindrical tube and its characteristics are presented in this paper. The conclusion is that this new detector design is a major improvement for correct dose and dose profile measurements in CT systems.

     

     

  • 14.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Design, Fabrication and Optimization of Thermal Radiation Detectors Based on Thin Polymer Membranes2009Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The number of applications in which infrared radiation sensors are used is increasing. In some applications, the cost of the sensor itself is an issue, and simple solutions are thus required. In this thesis, the investigations have related to the use of thin polymer membranes in thermal infrared sensors, such as bolometers and thermopiles.

    Infrared sensors are usually subcategorized into photonic sensors and thermal sensors. For detection of infrared radiation using a photodetector, there is a requirement for low band-gap material. The need of cooling makes infrared photodetectors rather expensive, and not an alternative for low-cost applications. In thermal sensors, the heat generated from the incident infrared radiation is converted into an electrical output by means of a heat sensitive element. Thermal sensors operate at room temperature, which makes them a low-cost alternative. The basic structure of thermal sensors consists of a temperature sensitive element connected to a heat sink through a structure with low thermal conductance. It is common to use thin membranes of Silicon or Silicon Nitride as thermal insulation between the heat sink and the sensitive element. In comparison, polymers have a thermal conductance that is lower than in these materials, and this increases the generated temperature in the sensitive element. A polymer such as SU-8 has a low thermal conductivity and is applied using a spin coater. This reduces the number of complex processing steps. This thesis presents a new application of SU-8 as a closed membrane in a thermal sensor.

    The concept was initially demonstrated by fabricating a nickel bolometer and titanium/nickel thermopile structure with a 5 µm SU-8 / SiO2 membrane. However, for the sensor responsivity to be able to compete with commercial thermal sensors the structures, some optimization was required. Since the thermopile generates its own voltage output and requires no external bias, the optimizations were focused on this structure. There exist a number available software tools for thermal simulation of components. However, to the author’s best knowledge, there exist no tool for design optimization of thermopiles with closed membranes. An optimization tool using iterative thermal simulations was developed and evaluated. A new thermopile structure, based on the optimization results, was both fabricated and characterized. Using an infrared laser with a small spot, the measured responsivity of the manufactured thermopile was higher than that of a commercial sensor. In the case of a defocused spot and for longer wavelengths, the infrared absorption in the absorption layer reduces and degrades the responsivity.

    The thermopile was further evaluated as a sensor in a carbon dioxide meter application based on the NDIR principle. An increase in the CO2 concentration demonstrated a clear decrease in the thermopile voltage response, as was expected. By normalizing the voltage response and comparing it with a commercial sensor, this showed that the SU-8 based thermopile is relatively more sensitive to changes in the CO2 concentration.

  • 15.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Fabrication and Characterization of Photon Radiation Detectors2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis involves a study the fabrication and characterization of photon radiation detectors. The focus has been to develop and improve the performance of optical measurement systems, but also to reduce their cost. The work is based on the study of two types of detectors, the position sensitive detector and the thermal detector.

    Infrared detectors are usually subcategorized into photonic detectors and thermal detectors. In the thermal detectors, heat generated from the incident infrared radiation is converted into an electrical output by some sensitive element. The basic structure of these detectors consists of a temperature sensitive element connected to a heat sink through a thermally isolating structure. Thin membranes of Silicon and Silicon nitride have been commonly used as thermally insulation between the heat sink and the sensitive elements. However, these materials suffer from relatively high thermal conductivity, which lowers the response of the detector. The fabrication of these membranes also requires rather advanced processing techniques and equipment. SU-8 is an epoxy based photoresist, which has low thermal conductivity and requires only standard photolithography. A new application of SU-8 as a self-supported membrane in a thermal detector is presented. This application is demonstrated by the fabrication and characterization of both an infrared sensitive thermopile and a bolometer detector. The bolometer consists of nickel resistances connected in a Wheatstone bridge configuration, whereas the thermopile uses serially interconnected Ti/Ni thermocouple junctions.

    The position sensitive detectors include the lateral effect photodiodes and the quadrant detectors. Typical applications for these detectors are distance measurements and as centering devices. In the quadrant detectors, the active region consists of four pn-junctions separated by a narrow gap. The size of the active region in these detectors depends on the size of the light spot. In outdoor application, this spot size dependence degrades the performance of the four-quadrant detectors. In this thesis, a modified four-quadrant detector having the pn-junctions separated by a larger distance has been fabricated and characterized. By separating the pn-junctions the horizontal electric filed in the active region is removed, making the detector spot size insensitive.

    Linearity of the lateral effect photodiodes depends on the uniformity of the resistive layer in the active region. The introduction of mechanical stress in an LPSD results in a resistance change mainly due to resistivity changes, and this affects the linearity of the detector. Measurements and simulations, where mechanical stress is applied to LPSDs are presented, and support this conclusion.

  • 16.
    Mattsson, Claes
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Bertilsson, Kent
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Manufacturing and characterization of a modified four-quadrant position sensitive detector for out-door applications2004Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 531, nr 1-2, s. 134-139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Position sensing detectors (PSDs) are useful in many applications such as vibration, displacement and triangulation measurements. In this paper we have constructed a novel structure, which has higher inter-electrode resistance than a lateral effect PSD and is more robust to atmospheric turbulence than a conventional four-quadrant PSD (Nuclear Instruments and Methods in Physics Research A 466 (2001) 183). The detector structure is useful for applications with detector windows less than 0.5 x 0.5 mm(2), but the nonlinearity is the main concern for a detector of that size. Without any corrections for non-linearity the standard deviation of the error is 9 mum (2.2%). Using a simple analytical expression and a 2-d correction-function stored in a look-up table the positioning error is reduced to 6 (1.5%) and 2 (0.5%) mum, respectively.

  • 17.
    Mattsson, Claes
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Bertilsson, Kent
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Martin, Hans
    SenseAir.
    Thermal simulation and design optimization of a thermopile infrared detector with SU-8 membrane2009Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 19, nr 5, s. 055016-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Simulation and optimization tools are commonly used in the design phase of advanced electronics devices. In this work, we present a thermal simulation and design optimization tool for infrared thermopile detectors based on a closed membrane structure. The tool can be used to simulate and optimize thermopile detectors with an arbitrary number of design parameters. The optimization utilizes the Nelder–Mead and the adaptive simulated annealing optimization algorithms to maximize the system performance. A thermopile detector with an SU-8-based closed membrane and metal–metal thermocouples has been simulated and optimized. Based on the results generated by the tool, an optimized detector has been fabricated and characterized. The results from the measurements presented are in good agreement with the simulation results.

  • 18.
    Mattsson, Claes
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Bertilsson, Kent
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Martin, Hans
    SenseAir AB.
    Design of a Micromachined Thermopile Infrared Sensor with a Self-Supported SiO2/SU-8 Membrane2008Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 8, nr 12, s. 2044-2052Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the infrared region of the spectrum thermoelectric detectors such as the thermopile, are extensively used. These detectors rely on the well-known Seebeck effect, in which there is a direct conversion of thermoelectric differentials into electrical voltage. The temperature difference over thermocouple junctions is in general, created by forming a thin membrane connected to the silicon bulk. In many existing thermopiles, materials such as Si and Si3N4 have been used as membrane. These materials suffer from relatively high thermal conductivity, which lowers the membrane temperature and reduces the sensitivity of the detector. A material such as SU-8 2002 has a much lower thermal conductivity and is applied using standard photolithographic processing steps. This work presents thermal simulations regarding the use of SU-8 2002 as a thermal insulating membrane as compared to Si and Si3N4. The simulation results presented show that the temperature increase in a 5 µm SiO2/SU-8 membrane is about 9% higher than in a 1 µm Si3N4 membrane, despite the membrane thickness being increased by a factor of 5. A thermopile consisting of 196 serially interconnected Ti/Ni thermocouples positioned on a 5 µm SiO2/SU-8 2002 membrane has been fabricated. The sensitivity of the fabricated device has been evaluated in the infrared region, using a 1.56 µm IR laser and a xenon arc lamp together with a monochromator. The measurement results show a sensitivity of approximately 5 V/W over the wavelength range between 900 - 2200 nm. Measurements performed in a vacuum chamber show that the sensitivity of the detector could be increased by more than a factor of 3 by mounting the detector in a vacuum sealed capsule.

  • 19.
    Mattsson, Claes
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Bertilsson, Kent
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Martin, Hans
    Development of an infrared thermopile detector with a thin self-supporting SU-8 membrane2007Ingår i: Proceedings of IEEE Sensors, New York: IEEE conference proceedings, 2007, s. 836-839Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we present the development and characterization of thermopile detector on a 4 mum thin self-supporting membrane made of the epoxy based photoresist SU-8. The membrane is realized using silicon bulk micromachining techniques. In many existing thermopile detectors, a temperature difference over the thermocouple junctions is achieved by connecting a thin membrane of either Si or Si3N4 to a silicon bulk. These materials suffer from relatively high thermal conductivity, which lowers the sensitivity of the detector. A material such as SU-8 has much lower thermal conductivity and is applied using standard photolithographic processing steps. Simulation results are presented which verifies SU-8 as a better choice than Si and Si3N4 when used as thermal insulating membrane in a thermopile detector. A thermopile consisting of 196 series coupled Ti/Ni thermocouples has been fabricated. Results from measurements are presented, showing a sensitivity of 5.6 V/W and a noise equivalent power (NEP) of 9.9 nW/radicHz.

  • 20.
    Mattsson, Claes
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Bertilsson, Kent
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Martin, Hans
    SenseAir.
    Fabrication and characterization of a design optimized SU-8 thermopile with enhanced sensitivity2009Ingår i: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 20, nr 11, s. 115202-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the infrared wavelength region, thermopiles are an important type of detectors. A major advantage of thermopiles is their non-cooling requirement. Depending on the applied absorption layer, their responsivity is often rather flat within a large wavelength region. This work presents the fabrication and characterization of a sensitivity and design optimized thermopile detector with a 4 µm self-supported SiO2/SU-8 membrane. The structure consists of 240 series interconnected thermocouple junctions obtained by a metal evaporation and lift-off. Two metal combinations have been evaluated, namely, nickel/titanium and aluminium/bismuth. Series resistances of 76 k and 283 k were measured for the Ni/Ti thermopile and the Al/Bi thermopile respectively. For the Al/Bi thermopile a responsivity of 60 V/W was achieved using a 1.56 µm fibre coupled diode laser with a power of 3.5 mW. Using a white light source with a radiation flux of 0.45 W/mm2 a voltage response of 68 V mm2/W was measured for the Al/Bi thermopile. The time constant of the characterized detectors was calculated as being 70 ms, using the pulsed IR laser.

  • 21.
    Mattsson, Claes
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Bertilsson, Kent
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Martin, Hans
    Fabrication and evaluation of a thermal sensor formed on a thin photosensitive epoxy membrane with low thermal conductivity2008Ingår i: PROCEEDINGS OF THE 17TH INTERNATIONAL VACUUM CONGRESS/13TH INTERNATIONAL CONFERENCE ON SURFACE SCIENCE/INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY, Institute of Physics (IOP), 2008, s. 082048-Konferensbidrag (Refereegranskat)
    Abstract [en]

    This article present the fabrication and development of a thin metal film bolometer IR detector connected in a Wheatstone bridge configuration. The bolometer is constructed on a 4 μm thin self-supported SU-8 2002 membrane. A polymer material such as SU-8 has low thermal conductivity and is applied using standard photolithographic processing step, and this could increase detector sensitivity and lower the production cost. Thermal simulation results are presented, which verifies SU-8 as a better choice of materials compared to common membrane materials such as Si and Silicon nitride. Measurements on the fabricated nickel resistance bolometer on SU-8 2002 membrane show a sensitivity of 9.3 V/W when radiated by an IR laser with a wavelength of 1.56 μm.

  • 22.
    Mattsson, Claes
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Thungström, Göran
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Rödjegård, Henrik
    SenseAir.
    Nilsson, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Martin, Hans
    SenseAir.
    Experimental evaluation of a thermopile detector with SU-8 membrane, in a carbon dioxide meter setup2009Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 9, nr 12, s. 1633-1638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Continuous control of the carbon dioxide levels in the ventilation systems in office buildings and public schools has been shown to increase productivity and save money. However, these measurement systems require further developments in order to be more cost effective. This paper presents an evaluation of an Al/Bi thermopile detector with a 4 µm thin SiO2/SU-8 membrane in a CO2 meter application using the NDIR (Non-Dispersive Infrared Technology). The system consists of an 11 cm aluminum tube, used as the sample chamber and in which a light source and a thermopile detector with a 4.26 µm optical bandpass filter are positioned on its opposite sides. The light source is pulsed with a frequency of 0.5 Hz. The voltage response of the Al/Bi thermopile is measured for different CO2 concentrations, and, as expected according to the Lambert-Beer law, there is an exponential decrease in the measured intensity. The absolute response is about 50 % lower than for a commercial HMS J21 thermopile from Heimann Sensor GmbH. In relative terms, on the other hand, the Al/Bi thermopile is more sensitive for changes in the CO2 concentration. At 7500 ppm, the voltage response has decreased to 40 % of the reference response measured in the nitrogen atmosphere.

  • 23.
    Nilsson, Hans-Erik
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Norlin, Börje
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Fröjdh, Christer
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Bethke, K
    PANalytical B.V, Netherlands.
    De Vries, R
    PANalytical B.V, Netherlands.
    Evaluation of the charge sharing effects on spot intensity in XRD setup using photon counting pixel detectors2005Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 563, nr 1, s. 182-186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study we examine how charge loss due to charge sharing in photon counting pixel detectors affects the recording of spot intensity in an X-ray Diffraction (XRD) setup. In the photon counting configuration the charge from photons that are absorbed at the boarder of a pixel will be shared between two pixels. If the threshold is high enough these photons will not be counted. However, if the threshold is low enough these photons will be counted twice. In an XRD setup the intensity and position of various spots should be recorded. Thus, the intensity measure will be affected by the setting of the threshold. In this study we used a system level Monte Carlo simulator to evaluate the variations in the intensity signals for different threshold settings and spot sizes. The simulated setup included an 8keV monochromatic source (providing a Gaussian shaped spot) and the MEDIPIX2 photon counting pixel detector (55 µm x 55 µm pixel size with 300µm silicon) at various detector biases. Our study shows that the charge sharing distortion can be compensated by numerical post processing and high resolution in both charge (charge distribution?) and position can be achieved.

  • 24.
    Thungström, Göran
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Mattsson, Claes
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för informationsteknologi och medier.
    Rönnqvist, Camilla
    Fabrication and Characterization of Silicon Detectors for use in Radiotherapy Dosimetry, Pre-irradiated by High Energy Electrons2007Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 576, nr 1, s. 209-214Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fabricated silicon detectors for use in radiotherapy dosimetry have been pre-irradiated by means of 10 MeV electrons. The purpose of this irradiation is to saturate the diffusion carrier length in order to achieve linear dose rate dependence. A characterized n+p-detector has a relatively flat sensitivity slope after pre-irradiation and the detector exhibits a low leakage current and high shunt-resistance. The int. E-detector has a constant sensitivity slope for all doses and consequently requires no pre-irradiation. Due to a larger generation carrier volume, the leakage current and shunt-resistance are respectively higher and lower in comparison to the n+p-detector. After the annealing of the detectors has taken place, the n+p has the lowest leakage current and there is already significant recovery at 200 ˚C. The int. E detector has a constant sensitivity response to all the applied doses and performed annealing. The leakage current for the int. E detector improved to acceptable values after a FGA step was performed. An unacceptably high leakage current and low shunt-resistance means that the E-detectors are not considered to be useful for this application.

1 - 24 av 24
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