Materials and Processes for Bulk Antimony-based Substrate Materials

GaSb substrates are attractive for higher temperature infrared detectors for space-based and stealth applications. However, substrate inconsistency inhibits their widespread commercial application. In particular, producing damage-free GaSb surfaces and sub-surfaces with an easily desorbed oxide for epi-growth is difficult. Recently, bromine ion-beam assisted etching (Br-IBAE) was effective in removing surface damage and leaving a desorbable oxide on GaSb pieces. A full wafer nanoscale-modification process using oxygen gas-cluster ion beams (O2-GCIB) has also provided improved GaSb surfaces and sub-surfaces. However, O2-GCIB leaves a thick oxide requiring extended desorbtion time prior to device growth. An opportunity exists to establish a manufacturing method for obtaining GaSb surfaces and sub-surfaces of consistent integrity with a readily-desorbable oxide. Phase I will combine the Br-IBAE concept with full-wafer GCIB technology through a modified bromine gas-cluster source. In Phase I, the state-of-the-art CMP, Br-GCIB and Br-GCIB process matrices will be compared for "epi-readiness". Antimonide-based strained-layer superlattices will be gown on promising substrates, with particular attention to oxide desorbtion and substrate/heteroepitaxy quality. Successful GaSb substrates will be deliverables. Phase II determines device and manufacturing capability using modified, "epi-ready" specifications. High probability for successful commercialization is anticipated, with focused commitment to provide superior substrates to military and commercial markets.