Quality Improvement of GaN Epi-layers Grown with a Strain-Releasing Scheme on Suspended Ultrathin Si Nanofilm Substrate

Abstract

The material quality of III-nitrides is severely limited by the lack of cost-effective substrates with suitable lattice and thermal expansion coefficients. A suspended ultrathin silicon membrane substrate ($$\sim$$ ∼ 16 nm), fabricated by an easy process on SOI substrates, is thus designed for nitride epitaxial growth, which can effectively release the strain in the epi-layers, and has demonstrated large-area (Al)GaN growth with a smooth surface and greatly reduced defect density. This research provides a promising CMOS-compatible method for growing cost-effectively high-quality III-nitrides that can be used for the development of high-performance devices.