Study On The Transport Properties Of GaN-based Heterojunction Two-dimensional Electron Gas

GaN HEMT-applications including high frequency and high-power microwave devices, pressure sensor, biological detection, etc., and has an important prospect and status, and the performance of the HEMT devices depends on the transport properties of2DEG In order to improve the HEMT devices performance, on the one hand, we need to raise2DEG sheet density, on the other hand also need to improve the mobility of2DEG This paper will study GaN based HEMT including AlxGa1-xN/GaN heterostructure and AlxGa1-xN/AlN/GaN double heterojunction on the interface between the two-dimensional electron gas distribution, surface density, as well as by scattering and mobility of the theoretical calculation study and discuss in detail.Firstly we introduces AlxGa1-xN/GaN heterostructure properties and structure, and analysis its interface due to the spontaneous polarization effect and piezoelectric polarization effect produced by the surface charge density, and gathered near the interface of two dimensional electron gas distribution, surface density and subband energy level structure.Then we illustrated the general process of electron scattering calculation and gave the AlxGa1-xN/GaN heterostructure materials in some of the major scattering mechanisms, including the interface roughness scattering, alloy disorder scattering, polar optical phonon scattering processing method.In the end, this paper investigated the changes of electron transport properties in AlxGa1-xN/GaN with an inserted AlN layer. The polarization charge density and two-dimensional electron gas (2DEG) sheet density in AlxGa1-xN/AlN/GaN double heterojunction high electron mobility transistors (HEMT) affected by the spontaneous polarization and piezoelectric polarization in AlxGa1-xN and AlN barrier are considered, also the relationship of interface roughness scattering and alloy disorder scattering with the AlN thickness is systematically analyzed. The results indicated that2DEG sheet density, interface roughness scattering and alloy disorder scattering evidently depended on the thickness of the inserted A1N layer.2DEG sheet density and mobility greatly increased by inserting a A1N layer about1-3nm.