Thermal Imaging Using Indium Doped Silicon

Abstract

On indium doped silicon monolithic integrated focal plane arrays with 64 x 64 picture elements were developed. The chip size is 56 mm2, the pixel size 551μm x 65 μm, the pitch 85/μm, and the fill fator 50 %. The black body (500K) detectivity of the image sensor is 2 x10 11 cm W -1 sec -1/2 and the inhomogenity of the responsivity less than 5 %. The significant features of the array are - picture elements operating with punch through technique (inherent antiblooming) - resistive gate structure for the read-out in the vertical direction - 4 phase CCD for serial read-out in the horizontal direction Using this device a camera system has been built to demonstrate the possibilities for thermal imaging with extrinsic silicon. The output signals are processed with the double correlated sampling method. To fully utilize the performance capability of the device it is necessary to compensate offset and gain nonuniformities. The demonstration system is built up with a pixel-by-pixel offset compensation with 10 bit correction factors.