The effect of dislocation-related V-shaped pits preparation on the strain of AlN templates

Abstract

Herein, the dislocation defects of an aluminum nitride (AlN) template heteroepitaxially grown by metal-organic chemical vapor deposition are exposed by phosphoric acid etching. The effect of dislocation-related V-shaped pits preparation on the strain of AlN epilayer is intensively studied. The results show that the dislocation defect etching leads to a strain gradient elongating along the growth direction of AlN and alleviates its initial tensile strain. Through a secondary epitaxy on the dislocation-etched AlN, it further reveals that the strain evolves into compressive strain state accompanied by surface cracking inhibition. It provides an effective way of stress regulation by dislocation-related etching and can be developed as a mask-free lateral epitaxial growth technique for high-performance AlN template preparation.