.algan / Gan Heterostructure Materials And Devices Research

AlGaN/GaN heterostructures have attracted people's more and more attention for its advantageous using in fields like high temperature, high frequency and high-power, researches on its material and devices have been the front and hot point in the area of microelectronics. This thesis will mainly discuss the characteristics of AlGaN/GaN heterostucture material and devices, including researches by numeric method calculation on tow-dimension electronic gas (2DEG); surface potential pinning-off effect; some parameters of AlGaN/GaN HFET and the thermal stability of AlGaN/GaN heterostructures. The mainly results are as follows,1) Self-consistent solution of SchrOdinger-Poisson equations has been done successfully by Matlab, and conduction band, subband and the density of 2DEG have been obtained. Density of polarization charge in AlGaN barrier layer has been calculated.2) Surface potential pinning-off effect can't be proved existing in AlGaN/GaN heterostructures prepared by MOCVD.3) With C-V measurement curves, a new method has been found to get threshold voltage for AlGaN/GaN HFET, and with the threshold voltage, the pinch-off voltage for AlGaN/GaN HFET has been obtained too.4) Thermal stability of AlGaN/GaN heterostructure Schottkey contacts has been investigated by thermal stress experiments and computer simulation. It is shown that after 700℃, 30minutes thermal stressing, the Schottky barrier height of AlGaN/GaN heterostructure is increased, and both the density of 2DEG and the density of polarization charge for AlGaN/GaN heterostructures are reduced.