Development of a Monolithically Integrated HgCdTe Megapixel IRFPA

The Fabrication of large format mid and long wavelength (MWIR and LWIR) mercury cadmium telluride based staring focal plane array (FPAs) is highly desirable for DOD applications such as surveillance and target acquisition missions. However, the development of large FPAs has been seriously impeded by the limited size of commercially available Cd(1-x)Zn(x)Te substrates and in the current hybrid technology by the thermal expansion mismatch between HgCdTe detector array and Si readout. In this project, we propose to explore the development of a monolithically integrated HgCdTe megapixel IRFPA High quality (defect density less than 5x10(5) cm(-2)) (211)B Cd(1-x)Zn(x)Te epitaxial layers will be grown by molecular beam epitaxy (MBE) on 3-inch Si(211) substrates. Device quality p-on-n MWIR HgCdTe heterostructures will be grown also by MBE on these 3-inch lattice matched Cd(1-x)Zn(x)Te/Si substrates and photodiodes will be processed and tested. In order to develop, in Phase II, a LWIR HgCdTe IRFPA monolithically integrated with the readout circuit on a common silicon wafer, an advanced device architecture with an extended field of view will be designed in Phase I. A particular attention will be given to the temperature during the entire growth and fabrication process which should not exceed the maximum temperature allowed for a Si readout circuit. In order to evaluate the feasibility of the monolithic concept, localized epitaxy of CdTe on Si substrates will be explored. BENEFITS: The anticipated benefits of this R & D project would be the development of robust, low cost, advanced and very large format long wavelength IRFPAs. Large high performance IRFPAs are needed in many military and commercial applications.