摘要
The mobility of the two-dimensional electron gas （2DEG） in AIGaN/GaN hetero-structures changes significantly with AI content in the AIGaN barrier layer, while few mechanism analyses focus on it. Theoretical calculation and analysis of the 2DEG mobility in AIGaN/GaN heterostructures with varied AI content are carried out based on the recently reported experimental data. The 2DEG mobility is modeled analytically as the total effects of the scattering mechanisms including acoustic deformation-potential, piezoelectric, polar optic phonon, alloy disorder, interface roughness, dislocation and remote modulation doping scattering. We show that the increase of the 2DEG density, caused by the ascension of the AI content in the barrier layer, is a dominant factor that leads to the changes of the individual scat- tering processes. The change of the 2DEG mobility with AI content are mainly determined by the interface roughness scattering and the alloy disorder scattering at 77 K, and the polar optic phonon scattering and the interface roughness scattering at the room temperature. The calculated function of the interface roughness pa- rameters on the AI content shows that the stress caused AIGaN/GaN interface degradation at higher AI content is an important factor in the limitation of the in- terface roughness scattering on the 2DEG mobility in AIGaN/GaN heterostructures with high AI content.
The mobility of the two-dimensional electron gas （2DEG） in AIGaN/GaN hetero-structures changes significantly with AI content in the AIGaN barrier layer, while few mechanism analyses focus on it. Theoretical calculation and analysis of the 2DEG mobility in AIGaN/GaN heterostructures with varied AI content are carried out based on the recently reported experimental data. The 2DEG mobility is modeled analytically as the total effects of the scattering mechanisms including acoustic deformation-potential, piezoelectric, polar optic phonon, alloy disorder, interface roughness, dislocation and remote modulation doping scattering. We show that the increase of the 2DEG density, caused by the ascension of the AI content in the barrier layer, is a dominant factor that leads to the changes of the individual scat- tering processes. The change of the 2DEG mobility with AI content are mainly determined by the interface roughness scattering and the alloy disorder scattering at 77 K, and the polar optic phonon scattering and the interface roughness scattering at the room temperature. The calculated function of the interface roughness pa- rameters on the AI content shows that the stress caused AIGaN/GaN interface degradation at higher AI content is an important factor in the limitation of the in- terface roughness scattering on the 2DEG mobility in AIGaN/GaN heterostructures with high AI content.
基金
Supported by the Key Program of the National Natural Science Foundation of China (Grant No.60736033)
Xi’an Applied Materials Innovation Fund (Grant No. XA-AM-200703)
the Open Fund of Key Laboratory of Wide Bandgap Semiconductors Material and Devices, Ministry of Education, China
