Pseudomorphic Semiconducting Heterostructures from Combinations of AlN, GaN andSelected SiC Polytypes: Theoretical Advancement and its Coordination with Experi mental Studies of Nucleation, Growth, Characterization and Device Development

摘要

The use of NH3 as an alternative to ECR in the gas source(GS) MBE of GaN hasresulted in an increase in the growth rate and a sharp peak at 354 nm in the PL spectrum. The use of an ammonia cracker cell was investigated. Stoichiometric GaN films have also been deposited on Al2O3(0001), Si(001) and Si(111) substrates using an NH3 seeded free He jet and an effusive triethylgallium (TEG) source. Very uniform films have been achieved at low temperatures. Work continues toward the construction of a dual supersonic beam deposition system with an attached UHV analysis system. The results of GaN film deposition in the current single beam system and progress toward the completion of the next system are detailed. MIS diodes (Al/AlN/Alpha-SiC)(0001) were fabricated with various thicknesses of AlN by GSMBE. High frequency C-V measurements between 10kHz and 1 MHz showed that thin layers (1000A) of AlN exhibited moderate leakage currents; thicker layers reduced this problem. The diodes could be accumulated and depleted over the entire frequency range studied. Inversion was not achieved at room temperature. A dependence of the dielectric constant on frequency was also observed. jg.