Optimization of high-quality gallium nitride thin films deposited on silicon substrates with an aluminum nitride buffer layer through radio-frequency magnetron sputtering

In this study, high-quality GaN thin films were deposited on Si (111) substrates with an AlN buffer layer through radio-frequency (RF) magnetron sputtering. The sputtering parameters for the AlN buffer layer were optimized to enable subsequent high-quality GaN deposition. GaN thin films with a thickness of 300 nm were deposited in situ by using Ga metal as the sputtering target with N2 gas for performing reactive sputtering at a temperature of 600 degrees C and an RF power of 350 W. X-ray diffraction analysis confirmed the presence of a crystalline phase in the (002) plane at 2 theta = 34.5 degrees for the sputtered GaN thin films. Photoluminescence spectroscopy conducted at 100 K revealed that the GaN thin film had an emission peak at 3.37 eV (367 nm). The results of transmission electron microscopy and X-ray photoelectron spectroscopy verified that high-quality GaN thin films were formed over AlN buffer layers. The findings of this study suggest that RF-sputtered GaN films on Si substrates can be applied in electronic and optoelectronic devices.