Importance

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Abstract

An uncooled thermal detector (10) includes a MIS capacitor (12) that is suspended from a material (26, 26a) having a low thermal conductivity. The MIS capacitor includes a doped semiconductor body portion (14) having a gate dielectric (20), a gate electrode (22), and a second electrode (24) disposed over a surface thereof. In operation, the capacitance of the MIS capacitor at a frequency near a high-frequency/low-frequency transition is measured or sensed. As the temperature of the MIS capacitor increases, the sensed capacitance increases because minority carriers are able to respond faster to a modulating gate voltage. Similarly, if the temperature decreases, the sensed capacitance decreases, because the minority carriers respond more slowly. A high thermal coefficient of capacitance (> 20%/K) is achieved at all gate bias values for which the MIS capacitor is in inversion. By a suitable choice of doping level and the introduction of a deep level (24) to control the minority-carrier lifetime, the transition frequency may be tailored to a desired operating frequency at a given temperature. A method for fabricating the uncooled detector, and an array of same, within a Si film (2) of an SOI wafer (1) is also disclosed.

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First Claim