Chemical vapor deposition growth of β-Ga2O3 on Si- and C- face off-axis 4H–SiC at high temperature

Abstract

Realization of β-Ga2O3 on a high-thermal-conductivity substrate is crucial to overcome the poor thermal conductivity of β-Ga2O3 which is one of the major roadblocks against its era in power electronics. We investigated low-pressure chemical vapor deposition (LPCVD) growth on both Si and C- face (0001) 4H–SiC at a high growth temperature of 925 °C using Ga metal and O2 gas source. Growths on C-face 4H–SiC resulted polycrystalline β-Ga2O3 for the entire O2-flow range, whereas under optimized O2-flow conditions, step flow growth of (−201) β-Ga2O3 was achieved on Si-face 4H–SiC with 3.7 nm rms surface roughness and rocking curve FWHM of 0.54° at a growth rate reaching 2.48 μm/h 4° off-axis nature of the substrate promoted the growth of some of the in-plane rotational domains while suppressing others. Raman measurements further verified the pure β-Ga2O3 nature of the grown films. Using a customized LPCVD with solid source Ga, a cost-effective, safe and industrially scalable method was shown to pave the way to enable β-Ga2O3 heteroepitaxy on 4H–SiC for high-power electronics.