High mobility AlGaN/GaN heterostructures grown on Si substrates using a large lattice-mismatch induced stress control technology

摘要

A large lattice-mismatch induced stress control technology with a low Al content AlGaN layer has been used to grow high quality GaN layers on 4-in. Si substrates. The use of this technology allows for high mobility AIGaN/GaN heterostructures with electron mobility of 2040 cm~2/(V·s) at sheet charge density of 8.4 × 10~(12)cm~(-2). Strain relaxation and dislocation evolution mechanisms have been investigated. It is demonstrated that the large lattice mismatch between the low Al content AlGaN layer and AlN buffer layer could effectively promote the edge dislocation inclination with relatively large bend angles and therefore significantly reduce the dislocation density in the GaN epilayer. Our results show a great potential for fabrication of low-cost and high performance GaN-on-Si power devices.