THERMAL IMAGING CAMERA WITH LINEAR PB1-XSNXSE-ON-SI INFRARED-SENSOR ARRAY AND COMBINED JFET CMOS READ-OUT ELECTRONICS/

A thermal imaging camera for the 8-12 mu m wavelength range is describ ed which employs a new infrared sensor device and read-out principle. A bilinear 2 x 128 element infrared sensor array is fabricated in a na rrow gap Pb1-xSnxSe layer grown epitaxially on a Si-substrate. A appro ximate to 30 Angstrom thick intermediate epitaxial CaF2 buffer layer i s used for compatibility reasons. The read-out electronics chips conta in, for each sensor, an integrator with a low noise JFET input transis tor, correlated multiple sampling, and a sample and hold amplifier. Th ey are wire-bonded to the sensor array and operated at 80-120 K. The J FET input transistors allow to amplify from much lower source impedanc es (down to < 10 k Ohm) than with CMOS design without adding significa nt noise. Therefore, infrared sensors with lower impedances can be use d, which allows operation at higher temperature, or to use sensors wit h longer cut-off wavelengths.