ABSTRACTAluminum nitride (AlN) and gallium nitride (GaN) thin films have potential uses in high temperature, high frequency (e.g. microwave) acoustic devices. In this work, the piezoelectric coefficients of wurtzite AlN and GaN/AlN composite film grown on silicon substrates by molecular beam epitaxy were measured by a Mach-Zehnder type heterodyne interferometer. The effects of the substrate on the measured coefficients are discussed.
Gallium nitride heterostructures were grown on silicon substrates by metalorganic chemical vapour deposition. Substrate plastic deformations that occur during the growth process with the effective compressive stresses accumulation in the film were observed at temperatures of 930oC-975oC. An approach of silicon controlled plastic deformation by high-temperature annealing combined with the in situ SiNx layer growth after heterostructure epitaxy is proposed. This approach would simplify optimization of the gallium nitride heterostructures architecture for various technological tasks.
Transmission Electron Microscopy to Study Gallium Nitride Transistors Grown on Sapphire and Silicon Substrates
