| 1. |
- Andersson, Henrik, et al.
(författare)
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Processing and Characterization of a MOS Type Tetra Lateral Position Sensitive Detector with Indium Tin Oxide Gate Contact
- 2008
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:9-10, s. 1704-1709
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Tidskriftsartikel (refereegranskat)abstract
- A 2-D tetra lateral position sensitive detector (PSD) based on the metal-oxide-semiconductor (MOS) principle has been manufactured and characterized. The active area of the device is 5 nun x 5 mm and the intention is to use the central 4 nun x 4 nun for low nonlinearity measurements. The gate contact is made of indium tin oxide (ITO) that is a degenerate electrically conducting semiconductor, which, in addition, is also transparent in the visible part of the spectrum. The use of a MOS structure results in a processing with no necessity to use implantation or diffusion in order to make the resistive p-layer as in a conventional p-n junction lateral effect PSD. Position measurements show good linearity in the middle 4 nun x 4 mm area. Within the middle 2.1 mm x 2.1 mm, the nonlinearity is within 1.7% of the active area with a position detection error of maximum 60 mu m. Measured MOS IV characteristics are compared to a level 3 spice model fit and show good agreement. The threshold voltage is determined to be -0.03 V. Responsivity measurements show a high sensitivity in the visible spectral region.
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| 2. |
- Mattsson, Claes, 1978-, et al.
(författare)
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Design of a Micromachined Thermopile Infrared Sensor with a Self-Supported SiO2/SU-8 Membrane
- 2008
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Ingår i: IEEE Sensors Journal. - Piscataway, USA : IEEE. - 1530-437X .- 1558-1748. ; 8:12, s. 2044-2052
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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