Introducing voids around the interlayer of AlN by high temperature annealing

Abstract

Introducing voids into AlN layer at a certain height using a simple method is meaningful but challenging. In this work, the AlN/sapphire template with AlN interlayer structure was designed and grown by metal-organic chemical vapor deposition. Then, the AlN template was annealed at 1700 °C for an hour to introduce the voids. It was found that voids were formed in the AlN layer after high-temperature annealing and they were mainly distributed around the AlN interlayer. Meanwhile, the dislocation density of the AlN template decreased from 5.26 × 109 cm−2 to 5.10 × 108 cm−2. This work provides a possible method to introduce voids into AlN layer at a designated height, which will benefit the design of AlN-based devices.