The low-temperature mobility of two-dimensional electron gas in AlGaN/GaN heterostructures

作     者：张金风 毛维 张进城 郝跃 

作者机构：Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and DevicesMicroelectronics InstituteXidian University 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2008年第17卷第7期

页      面：2689-2695页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0704[理学-天文学] 

基　　金：supported by the Key Program of the National Natural Science Foundation of China (Grant No 60736033) Xi’an Applied Materials Innovation Fund of China (Grant No XA-AM-200703) the Open Fund of Key Laboratory of Wide Bandgap Semiconductors Material and Devices,Ministry of Education,China 

主　　题：two-dimensional electron gas mobility AlGaN/GaN heterostructures interface roughness 

摘      要：To reveal the internal physics of the low-temperature mobility of two-dimensional electron gas （2DEG） in Al- GaN/GaN heterostructures, we present a theoretical study of the strong dependence of 2DEG mobility on Al content and thickness of AlGaN barrier layer. The theoretical results are compared with one of the highest measured of 2DEG mobility reported for AlGaN/GaN heterostructures. The 2DEG mobility is modelled as a combined effect of the scat- tering mechanisms including acoustic deformation-potential, piezoelectric, ionized background donor, surface donor, dislocation, alloy disorder and interface roughness scattering. The analyses of the individual scattering processes show that the dominant scattering mechanisms are the alloy disorder scattering and the interface roughness scattering at low temperatures. The variation of 2DEG mobility with the barrier layer parameters results mainly from the change of 2DEG density and distribution. It is suggested that in AlGaN/GaN samples with a high Al content or a thick AlGaN layer, the interface roughness scattering may restrict the 2DEG mobility significantly, for the AlGaN/GaN interface roughness increases due to the stress accumulation in AlGaN layer.