Research On The Anisotropic Transport Properties Of Arriers In Non-polar GaN

GaN-based semiconductor materials are the most important wide and direct bandgap semiconductor material. GaN material has lots of advantages, such as high electrondrift velocity, big band gap, good electrical properties, so it has wide range ofapplications in the lighting, missiles, radar, communications and aerospace. Thespontaneous and piezoelectric polarization fields present in nitride hetero structures,while typically being advantageous in electronic devices such as nitride-based fieldeffect transistors, the strong electric field produced by spontaneous and strain-inducedpiezoelectric polarizations is in the c-axis oriented hexagonal GaN. An amount ofresearch has been done with respect to non-polar GaN. Transport properties ofnon-polar GaN are anisotropic, from the experimental facts; it is related to high densityof stacking faults. In this paper, some main scattering mechanisms are analyses and theanisotropic of electrons and holes mobility are discussed. The main results are brieflysummarized as follows:1. It is generally recognized that electrons and holes transport properties ofnon-polar GaN is analyses by the mode of non-degenerate.2. The electrons mobility firstly increased, and then decreased with temperatureand electrons concentration increase without considering the stacking faults. Theelectrons mobility in the X directionm BSFxand in the Y directionm BSFyalso firstlyincreased, and then decreased with temperature and electrons concentration increase inconsideration of stacking faults.m BSFxis generally lower thanm BSFy.However，thedifference betweenm BSFxandm BSFyis decreased with temperature and electronsconcentration increase. This trend is affect no only by the momentum relaxation of theother scattering mechanisms, but also by the transmission coefficient when the electrontunneling the stacking faults. It is a comprehensive effect.3. The trend of holes mobility with temperature and holes concentration increase issimilar to the trend of electrons mobility with considering the stacking faults or not. Thedifference betweenm BSFxandm BSFyis decreased with temperature and holesconcentration increase with considering the stacking faults. This trend has a significantdifference with the case of electrons because of the large effective mass of holes and thestrong neutral impurity scattering.