Monte Carlo Study On ZnO-based Semiconductor And ZnO MESFET

In recent years, ZnO and its ternary compound ZnMgO as wide band-gap semiconductors have drawn a great deal of interest and become one of hot toptics in research of optoelectronics and optical communications because of their excellent electrical and optical properties. According to the band structures calculated by first principles and different kinds scattering mechanisms, the three-valley Monte Carlo model for new semiconductors ZnO and ZnMgO is developed, then the steady-state and transient electron transport characteristics are investigated in-depth. Based on the model, considering the influence of surface state on the MESFET performance the device characteristics of ZnO MESFET are obtained for the first time. The main studies and conclusive results are as follows:1. Based on the band structures and relevant parameters calculated by first principles, the three-valley Monte Carlo model for ZnO and ZnMgO is established considering ionized impurity scattering, acoustic phonon deformation potential scattering, polar optical phonon scattering, intervalley scattering and alloy scattering, further, the velocity-field characteristics, mobility as a function of Mg content and the the drift velocity as a function of time are discussed.2. Considering the band structures and the basic material characteristics of ZnO, based on a geometry of ZnO MESFET device, a two-dimensional numerical Monte Carlo model for device simulation is employed. The distribution of potential and electric field and the output characteristics of device are achieved by tracking the electron transport and solving poisson’s equation. Further, based on the uniform distribution surface-state model, the influence of surface state between the source-gate and drain-gate regions on output characteristics of device is discussed. The research results can provide some theoretical references for designing optoelectronic and microelectronic devices with high quality and performance.