4英寸GaN衬底MOCVD外延高质量AlGaN/GaN HEMT材料研究分析

Study of High-quality AlGaN/GaN HEMT Homo-epitaxial Material on 4-inch GaN Substrate by MOCVD

本文对金属有机物化学气相淀积法在4英寸GaN衬底上生长出的高质量AlGaN/GaN HEMT外延材料进行了研究分析。生长过程采用NH_(3)/H_(2)混合气体及H_(2)交替通入的方法对衬底表面进行了预处理,阻隔了界面杂质的扩散。得益于衬底与外延的高度晶格匹配,GaN材料的螺位错密度降低到1.4×10^(7)cm^(-2),刃位错密度降低到3.0×10^(6)cm^(-2);非接触霍尔测试仪结果显示二维电子气迁移率为2159 cm^(2)/V·s,说明制备的材料晶体质量高且电学性能优异。此外,由于衬底与外延之间不存在热失配,使用拉曼光谱仪发现同质外延的Ga N E2(TO)峰位与衬底的E2(TO)峰位完全重合,表明同质外延过程中无应力应变产生。

High-quality AlGaN/GaN HEMT homo-epitaxial material grown on 4-inch GaN homo-substrate by metalorganic chemical vapor deposition(MOCVD)was studied in this paper.An alternation gas model of ammonia/hydrogen(NH_(3)/H_(2))mixed gas and H_(2)gas was employed to thermal treatment of GaN homo-substrate to prevent the spread of impurities.Due to the match of lattices,the density of screw dislocation was as low as 1.4×10^(7)cm^(-2)and the density of edge dislocation reached 3.0×10^(6)cm^(-2).The contactless Hall test results showed that the AlGaN/GaN HEMT material had a two-dimensional electron gas(2DEG)mobility of 2159 cm^(2)/V·s,indicating that the homo-epitaxial AlGaN/GaN HEMT material has high quality and good electrical performance.In addition,thanks to the absent thermal mismatch during the growth,the Raman spectrum test manifested that the peak positions of E2-high for GaN homo-substrate and the epitaxial material were totally coincident,showing that there was no strain in the homoepitaxial growth.