Influence of thermal stress on the characteristic parameters of AlGaN/GaN heterostructure Schottky contacts  

作　　者：吕元杰 林兆军 张宇 孟令国 曹芝芳 栾崇彪 陈弘 王占国 

机构地区：[1]School of Physics,Shandong University [2]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences [3]Laboratory of Semiconductor Materials Science,Institute of Semiconductors,Chinese Academy of Sciences

出　　处：《Chinese Physics B》2011年第4期430-434,共5页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No.10774090);the National Basic Research Program of China (Grant No.2007CB936602)

摘　　要：Ni Schottky contacts on A1GaN/GaN heterostructures have been fabricated. The samples are then thermally treated in a furnace with N2 ambient at 600℃ for different times （0.5, 4.5, 10.5, 18, 33, 48 and 72 h）. Current-voltage （I-V） and capacitance-voltage （C-V） relationships are measured, and SchrSdinger＇s and Poisson＇s equations are self- consistently solved to obtain the characteristic parameters related to A1GaN/GaN heterostructure $chottky contacts： the two-dimensional electron gas （2DEG） sheet density, the polarization sheet charge density, the 2DEG distribution in the triangle quantum well and the Schottky barrier height for each thermal stressing time. Most of the above parameters reduce with the increase of stressing time, only the parameter of the average distance of the 2DEG from the A1CaN/GaN interface increases with the increase of thermal stressing time. The changes of the characteristic parameters can be divided into two stages. In the first stage the strain in the A1GaN barrier layer is present. In this stage the characteristic parameters change rapidly compared with those in the second stage in which the AlGaN barrier layer is relaxed and no strain is present.Ni Schottky contacts on A1GaN/GaN heterostructures have been fabricated. The samples are then thermally treated in a furnace with N2 ambient at 600℃ for different times （0.5, 4.5, 10.5, 18, 33, 48 and 72 h）. Current-voltage （I-V） and capacitance-voltage （C-V） relationships are measured, and SchrSdinger＇s and Poisson＇s equations are self- consistently solved to obtain the characteristic parameters related to A1GaN/GaN heterostructure $chottky contacts： the two-dimensional electron gas （2DEG） sheet density, the polarization sheet charge density, the 2DEG distribution in the triangle quantum well and the Schottky barrier height for each thermal stressing time. Most of the above parameters reduce with the increase of stressing time, only the parameter of the average distance of the 2DEG from the A1CaN/GaN interface increases with the increase of thermal stressing time. The changes of the characteristic parameters can be divided into two stages. In the first stage the strain in the A1GaN barrier layer is present. In this stage the characteristic parameters change rapidly compared with those in the second stage in which the AlGaN barrier layer is relaxed and no strain is present.

关 键 词：AlGaN/GaN heterostructures thermal stressing polarization self-consistently solving SchrSdinger＇s and Poisson＇s equations 

分 类 号：TN303[电子电信—物理电子学]