Optimization of\nGrowth Temperature and V/III Ratio\ntoward High-Quality Si-Doped Aluminum Nitride Thin Films on Sapphire

Ultrawide-band-gap aluminum nitride (AlN) boasts high\nbreakdown\nfield strength, superior thermal conductivity, and exceptional stability,\nmaking it ideal for deep ultraviolet optoelectronics, radio frequency,\nand power devices. To date, the epitaxial growth of high-quality doped\nAlN via MOCVD has primarily been on AlN or SiC single-crystal substrates\nto reduce dislocation densities. However, the limited size and high\ncost of these single-crystal substrates necessitate the exploration\nof alternative substrates to enhance commercial viability. This study\ndemonstrates and analyzes the epitaxial growth modes and conductivity\nmodulation mechanisms of AlN:Si on a cost-effective sapphire substrate.\nBy adjusting MOCVD epitaxial parameters: growth temperature and V/III\nratio, we controlled the impact of compensating defects (C<sub>N</sub> and V<sub>Al</sub>) on conductivity, achieving conductivity enhancements\nof 26 and 41%, respectively. Our research validates the feasibility\nof obtaining AlN:Si with enhanced electrical performance and crystal\nquality on sapphire substrates. It represents a significant step toward\nthe development of high-power, high-efficiency AlN electronic devices.