Calculation of Temperature Coefficient of Resistance for Potential Barrier Structure for Bolometer in Uncooled Infrared Image Sensor

Abstract

A potential barrier structure is a candidate for producing high temperature coefficient of resistance (TCR) devices. The electrical characteristics of such a structure for application in a bolometer for an infrared image sensor are calculated on the basis of a thermionic electron emission theory and the effect of tunneling through the barrier layer. The TCR is obtained using the resistivity dependence on temperature and depends mainly on the barrier height. The TCR value is derived as a function of the barrier height, barrier thickness, and bias voltage to the structure. To obtain a TCR of greater than 0.04/K, the barrier height must be more than 0.3 eV. The resistivity also depends on barrier height. The thickness of the barrier layer is also important because it affects the resistivity and TCR. Proper design of a potential barrier structure will yield a bolometer film having a high TCR and low resistivity.