Infrared (IR) Materials Growth and Detector Processing Technology for Monolithic Dual-Band Detectors

The overall objective of this effort is to provide monolithic activity on GaAs/Si substrates for dual-band (3-5 and 8-12 micron) focal plane arrays (FPAs). More specifically to : 1) Determine the most promising GaAs/Si monolithic dual-band approach, 2) Identify Si readout (R/O) circuits, 3) Plan critical material and detector experiments, 4) Provide a monolithic dual-band FPA process, and 5) Layout FPAs and test circuits for 4" Si wafers. This effort will be based upon the authors' earlier work which replaced In bonds in hybrid FPAs by conformal thin films that interconnect HgCdTe detectors to R/Os in the same Si wafer. The proposed effort will extend this single-band monolithic technology to dual-band FPAs. The effort will determine the best dual-band unit cell in either a tandem or adjacent configuration using HgCdTe for the MWIR and either HgCdTe or AlGaAs quantum wells for the LWIR. R/O design will share charge between the unit cell capacitors and columns to increase signal-to-noise but yet maintain a small cell. The effort will plan experiments for processing the R/Os and detectors and for growing and fabricating detectors on GaAs/Si. The effort will deliver a dual-band process and a layout for 4" Si wafers that will include test structures and a 8 x 8 and another larger dual-band FPA.