Demonstration of 256 x 256 focal plane array based on Al-free GaInAs-InP QWIP

We report the first demonstration of an infrared focal plane array based on aluminum-free GaInAs-InP quantum-well infrared photodetectors (QWIPs). The long wavelength QWIP structure was grown via a low-pressure metal-organic chemical vapor deposition. Corrugated light coupling structure of QWIP was fabricated with a dry etching process. A 256/spl times/256 detector array was also fabricated with dry etching and hybridized to a Litton readout integrated circuit via indium bumps. A unique positive lithography method was developed to perform indium-bump liftoff. The noise equivalent differential temperature (NE/spl Delta/T) of 29 mK was achieved at 70 K with f/2 optics.