Strain Release in GaN Epitaxy on 4° Off-Axis 4H-SiC

A hybrid field-effect transistor (HyFET), superior for power electronic applications, can be created by harnessing the merits of two representative wide-bandgap semiconductors, gallium nitride (GaN) and silicon carbide (SiC). Yet, the incompactness in the epitaxy techniques hinders the development of the HyFET-GaN is usually grown on on-axis foreign substrates including SiC, whereas SiC homoepitaxy prefers off-axis substrates. This work presents a GaN-based heterostructure epitaxially grown on a conventional 4 degrees off-axis 4H-SiC substrate, which manifests its high quality and suitability for constructing GaN-based high-electron-mobility transistors, thereby suggesting a practical approach to realizing HyFETs. In the meanwhile, a distinct two-step biaxial strain-relaxation process is proposed and studied with comprehensive characterizations.

Automated summary

This work presents a hybrid field-effect transistor (HyFET) using GaN and SiC semiconductors and proposes a methodology for improving epitaxy techniques. The researchers successfully grown high-quality heterostructure on a conventional surface and also studied a two-step biaxial strain-relaxation process.