Evaluation of Gallium Nitride for Active Microwave Devices.
Annual rept. Apr 75-Mar 76,
UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES ELECTRONIC SCIENCES LAB
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At present we can routinely grow large, pure crystals of GaN, but because they are grown and processed under a non-equilibrium NH3 ambient instead of in N2, the maximum growth temperature is limited to 1050 deg. This induces a very high shallow donor density, as well as the precipitation of a second phase. While the latter might be improved by better control of growth parameters, the high carrier density necessitates processing at higher temperatures, where high pressure N2 must be used as the ambient. Furthermore, most normal semiconductor device processing steps can be accomplished only under such conditions. Hence the prime thrust of the efforts this past year has been in the design and assembly of such a high temperature-high pressure apparatus, and our efforts in CVD NH3 crystal growth and characterization have been aimed at producing crystals appropriate for high temperature processing annealing, diffusion, ion implantation and annealing, contacts, junctions.
- Electrical and Electronic Equipment
- Solid State Physics