Investigation of the interface electronic characteristics of β-Ga2O3 (1 0 0)/4H-SiC (0 0 0 1)

Abstract

Due to lower thermal conductivity of β-Ga2O3, gallium oxide power device based on high thermal conductivity substrates has received extensive attention. As a high thermal conductivity semiconductor material, 4H-SiC is suitable as a substrate to combine with β-Ga2O3 due to its small lattice mismatches. Herein, first principle is utilized to analyze the interfacial geometry structures, formation energy, interface binding energy and the electronic properties of the bonding mechanism at different β-Ga2O3 (100)/4H-SiC (0001) interfacial models. The interface formation energy and interface binding energy of β-Ga2O3 (100)/4H-SiC (0001) heterointerfaces are studied by using first principles. The results show that six different β-Ga2O3 (100)/4H-SiC (0001) heterostructures can be stable. Among the six interface models, Si-O interface possesses the smallest values of interface formation energy and interface binding energy after geometry relaxation, indicating highest thermodynamic stability. The differential charge density, bader charge, electron local function and partial density of states (PDOS) of β-Ga2O3 (100)/4H-SiC (0001) interface models are comprehensively investigated to understand the interfacial bonding strength and stability. It is shown that electrons are mainly transferred from the 4H-SiC side to the β-Ga2O3 side. Compared to other interface models, Si-O models, Si-GaO models can form strong Si-O chemical bond at the interface, while the interaction between the C-O models and C-GaO models forms a C-O bond with covalent bond properties.