chapter  12
19 Pages

Photoemissive Detectors

In 1973, Shepherd and Yang of Rome Air Development Center (Rome, New York) proposed the concept of silicide Schottky-barrier detector FPAs as a much more reproducible alternative to HgCdTe FPAs for infrared thermal imaging [1]. For the rst time it became possible to have much more sophisticated readout schemes-both detection and readout could be implemented in one common silicon chip. Since then, the development of the Schottky-barrier technology has progressed continuously and currently offers large IR image sensor formats. Despite lower quantum efciency (QE) than other types of infrared detectors, the PtSi Schottky-barrier detector technology has exhibited remarkable advances. Such attributes as monolithic construction, uniformity in responsivity and signal to noise (the performance of an infrared system ultimately depends on the ability to compensate for the nonuniformity of an FPA using external electronics and a variety of temperature references), and the absence of discernible 1/f noise make Schottky-barrier devices a formidable contender to the mainstream infrared systems and applications [2-9]. While PtSi Schottky-barrier detectors are operated in the short and middle wavelength infrared spectral bands, long wavelength infrared detectors have already been demonstrated with Si-based heterojunction infrared photoemission detectors. The photodetection mechanism in the later detectors is the same as that of the Schottky-barrier detectors.