PHOTOCONDUCTIVE IMPEDANCE-MATCHED INFRARED DETECTOR WITH HETEROJUNCTION BLOCKING CONTACTS

A photoconductive isotype heterjuction impedance-matched infrared detector has blocking contacts (66 and 68) which are positioned on the bottom side of the detector. Blocking contacts (66 and 68) prevent transfer of minority carriers from active region (42a) of the detector, thereby extending the lifetime of these carriers. The detector is formed by first fabricating active layer (42) followed by isotype blocking layer (44) on growth substrate (40). These layers are etched and appropriate passivation layers (93) and contacts (98 and 100) are applied. Mechanical supporting substrate (90) is applied to the detector and growth substrate (40) is removed. Etch stop holes (48 and 50) are formed which extend into active layer (42) of the detector. A precision thickness of active layer (42), required in an impedance-matched detector design, is produced by thinning active layer (42) in an etching process until the surface of active layer (42) reaches etch stop hole (48 and 50).