Influence of Ni Schottky contact thickness on two-dimensional electron-gas sheet carrier concentration of strained Al_（0.3）Ga_（0.7）N/GaN heterostructures

• Published in: Journal of semiconductors no. 8; pp. 74 - 77
• Main Author: 赵建芝 林兆军 马元杰 Corrigan Timothy D 孟令国 张宇 王占国 陈弘
• Format: Journal Article
• Language: Chinese
• Published: 2010
• Subjects: GaN; 二维电子气; 厚度偏差; 异质结; 气表; 肖特基接触; 载流子; 镍
• ISSN: 1674-4926

Ni/Au Schottky contacts with thicknesses of either 50（？）/50（？） or 600（？）/2000（？） were deposited on strained Al_（0.3）Ga_（0.7）N/GaN heterostructures.Using the measured C-V curves and I-V characteristics at room temperature,the calculated density of the two-dimensional electron-gas（2DEG） of the 600（？）/2000（？） thick Ni/Au Schottky contact is about 9.13×10~（12） cm~（-2） and that of the 50（？）/50（？） thick Ni/Au Schottky contact is only about 4.77×10~（12） cm~（-2）.The saturated current increases from 60.88 to 86.34 mA at a bias of 20 V as the thickness of the Ni/Au Schottky contact increases from 50（？）/50（？） to 600 A/2000 A.By self-consistently solving Schrodinger＇s and Poisson＇s equations,the polarization charge sheet density of the two samples was calculated,and the calculated results show that the polarization in the AlGaN barrier layer for the thick Ni/Au Schottky contact is stronger than the thin one.Thus,we attribute the results to the increased biaxial tensile stress in the Al_（0.3）Ga_（0.7）N barrier layer induced by the 600（？）/2000（？） thick Ni/Au Schottky contact.