Two color, Bias Selectable, HgCdTe Airborne Multispectrum Sensor Arrays

Spire proposes to design a multispectral infrared camera basaed on a two-color bias-selectable focal plane array fabricated in HgCdTe prepared by MOCVD. The proposed detector is a two terminal, HgCdTe, n-p-n heterostructure which can be thought of as two back-to-back diodes. Through proper selection of the materials composition and application of an appropriate bias, the device can be made sensitive to either 3-5 or 8-12 micron radiation. With good junction characteristics, background limited performance (BLIP) should be achievable in both bands. In addition, the device only requires two terminals such that a mosaic of detectors could be hybridized with a silicon signal processor using existing bump technology. In Phase I, Spire and its subcontractor Santa Barbara Focal Plane will design a two-color IR focal plane array camera and experimentally demonstrate the proposed two-color HgCdTe IR detector in MOCVD materials. Spire has successfully fabricated MOCVD two-color devices with cut-off wavelengths at 4.8 and 9.0 microns on bulk CdZnTe. In Phase II, we will apply an opimized device structure to MOCVD grown HgCdTe/CdZnTe/GaAs/Si and build a prototype 256 x 256 two-color focal plane array. The array will be integrated with an IR camera and deomonstrated in a portable brass-board system.