Wafer-scale single-crystalline β-Ga2O3 thin film on SiC substrate by ion-cutting technique with hydrophilic wafer bonding at elevated temperatures

Abstract

Heterogeneous integration of β-Ga2O3 on a highly thermal conductive SiC substrate is an efficient solution to solve its bottleneck of thermal dissipation for high-power electronics. In this work, a 2-inch high-quality \(\left( {\bar 201} \right)\) β-Ga2O3 single-crystalline film was transferred to the 4H-SiC substrate via the ion-cutting technique with hydrophilic bonding at elevated temperatures. The evolution process of the surface blistering on the hydrogen-implanted β-Ga2O3 together with the internal pressure in blisters were investigated systematically to understand the physical mechanisms of the ion-cutting of β-Ga2O3 thin film. As suggested by the finite element simulation, the hydrophilic bonding was carried out at an elevated bonding temperature of 96°C to prevent the debonding of β-Ga2O3/4H-SiC during the ion-cutting process via reducing the thermal stress. The as-transferred β-Ga2O3 thin film exhibited a narrow full width at half maximum of the X-ray diffraction of 79.2 arcsec, and an extremely smooth surface with a root-mean-square roughness of 0.1 nm was achieved after chemical mechanical polishing. It is expected that the β-Ga2O3/4H-SiC heterogeneous integration material obtained by the ion-cutting technique with hydrophilic bonding at elevated temperatures will serve as a practical platform for high-performance β-Ga2O3 power devices.