Si衬底GaN外延生长的应力调控

摘要

针对Si衬底GaN外延生长中由于张应力引起的表面裂纹问题,采用AlN/Al GaN多缓冲层结构和低温AlN插入层技术,在标准厚度Si(111)衬底上制备了100 mm(4英寸)无裂纹GaN外延材料.试验结果表明,AlN/Al GaN各层厚度的合理搭配和低温AlN插入层可以起到良好的应力调控效果,无裂纹GaN层生长厚度达到1.6μm,晶体质量良好,表面粗糙度低于2 nm;HEMT结构外延片电学性能测试结果表明Si衬底GaN的生长质量满足制备器件的要求.%This paper aims at solving the problem of surface crack caused by tensile stress in epitaxial growth of GaN on Si substrate. A 100 mm(4 inch)GaN epitaxial layer was prepared on a standard thickness Si(111)substrate using the AlN/Al GaN multi buffer layer structure and low temperature AlN insertion layer technology. The test results show that properly choosing the thickness of AlN/Al GaN layers and adopting the low temperature AlN insertion layer are quite effective in stress control. The growth thickness of the crack-free GaN layer reaches 1.6 μm, with a high crystal quality and a surface roughness lower than 2 nm. Electrical property test of the HEMT structure shows that the growth quality of GaN film on Si substrate meets the requirements of device fabrication.