Predicted Performance Improvement of Auger-Suppressed HgCdTe Photodiodes and p-n Heterojunction Detectors

Infrared detectors require cryogenic operation to suppress dark current, which is typically limited by Auger processes in narrow-band-gap semiconductor materials. Device structures designed to reduce carrier density under nonequilibrium reverse-bias operation provide a means to suppress Auger generation and to reduce dark current and subsequent cryogenic cooling requirements. This study closely examines mercury cadmium telluride (HgCdTe) p(+)/nu/n(+) device structures exhibiting Auger suppression, comparing the simulated device behavior and performance metrics to those obtained for conventional HgCdTe p(+)/nu detector structures. Calculated detectivity values of high-operating- temperature and double-layer planar heterojunction devices demonstrate consistently higher background limited performance (BLIP) temperatures over a range of cutoff wavelengths. BLIP temperature improvements of Delta T(BLIP) similar to 48 K and 43 K were extracted from simulations for midwavelength infrared and long wavelength infrared devices, respectively. These studies predict that Auger-suppressed detectors provide a significant advantage over conventional detectors with an increased operating temperature of approximately 40 K for equivalent performance for devices with cutoff wavelength in the range of 5-12 mu m.