Low Defect Density Substrates and High-Quality Epi-Substrate Interfaces for ABCS Devices and Progress Toward Phonon-Mediated THz Lasers

摘要

Over the past four years the University of Massachusetts Photonics Center, the Center for Advanced Materials and the Submillimeterwave Technology Laboratory in partnership with AFRL/SNHC has been developing technology for producing low defect density substrates and high-quality epi-substrate interfaces for ABCS device applications as well as developing fabrication and device concepts for incorporation into quantum-cascade THz lasers. During the course of the project a number of new technologies were developed and demonstrated. A new Bridgeman-magnetic-stirring antimonide bulk growth method was developed and using the method uniformly selinium n-type doped bulk GaSb crystals were grown; Bulk InGaSb crystals were grown; and GaAlSb bulk crystals were grown. In the areas of wafer polishing and epi-substrate interface control, novel gas cluster-ion-beam (GCIB) final polishing methods and bromine ion-beam assisted etching final polishing methods were developed that allow control of the epi-substrate interface when molecular beam epitaxy is employed for epigrowth. In the THz portion of the project novel Thz photonic crystals were demonstrated and new phonon mediated THz quantum cascade laser design developed. The ABCS polishing work was moved toward commercialization through two joint collaborations with Galaxy Compound Semiconductors, Inc, a Phase I SBIR to develop bromine-based GaSb GCIB polishing (AFRL) and a PhaseI/II project to develop novel final polishing techniques for GaSb and InSb wafers (DARPA). The THz work generated collaborations with Drs. T. Nelson and J.Ehret of WPAFB, Prof. Ram-Mohan of WPI/Quantum Semiconductor Algorithms, Inc. and Dr. Kurt Linden of Spire Corp.