Gallium-Doped Silicon Blocked-Impurity-Band Detectors

摘要

Boeing and Lawrence Semiconductor Research Laboratory are developing high-performance gallium-doped-silicon (Si: Ga) impurity-band-conduction material and Blocked-Impurity-Band (BIB) detectors. We build on a strong technology base in arsenic-doped silicon (Si:As) material and BIB detector technology. Si:As large-format focal plane arrays offer background-limited infrared performance (28 micrometers cut-off wavelength) and excellent pixel operability and uniformity to many defense and space imaging and spectroscopy applications. Application of Si:As BIB detectors to long-lifetime missions is restricted by operating temperature (10 K) below the range of available cooler technologies. The development of a Si:Ga option, with several degrees higher operating temperature, is intended to ease this restriction. The Si:Ga cut-off wavelength (18 to 20 micrometers) is suitable for many ground- and space-based applications. Known Si:Ga material development issues have been circumvented and detector-quality Si:Ga material and initial front- and back-illuminated BIB detector structures have been prepared and evaluated. We report dark current, quantum yield, and spectral response for prototype devices and discuss material and detector improvement directions.