用肖特基电容电压特性数值模拟法确定调制掺杂Al_xGa_(1-x)N/GaN异质结中的极化电荷  

EXTRACTION OF POLARIZATION-INDUCED CHARGE DENSITY INMODULATION-DOPED Al_xGa_(1-x)N/GaN HETEROSTRUCTURETHROUGH THE SIMULATION OF THE SCHOTTKY CAPACITANCE-VOLTAGE CHARACTERISTICS

作　　者：周玉刚[1] 沈波[1] 刘杰[1] 周慧梅[1] 俞慧强[1] 张荣[1] 施毅[1] 郑有炓[1] 

机构地区：[1]南京大学物理系,南京210093

出　　处：《物理学报》2001年第9期1774-1778,共5页Acta Physica Sinica

基　　金：国家重点基础研究专项 (批准号 :G2 0 0 0 0 6 83) ;国家自然科学基金 (批准号 :6 980 6 0 0 6 ;6 9976 0 14及 6 99870 0 1) ;国家

摘　　要：研究发展了用肖特基电容 电压特性数值模拟确定调制掺杂AlxGa1 -xN GaN异质结中极化电荷的方法 .在调制掺杂的Al0 2 2 Ga0 78N GaN异质结上制备了Pt肖特基接触 ,并对其进行了C V测量 .采用三维费米模型对调制掺杂的Al0 2 2 Ga0 78N GaN异质结上肖特基接触的C V特性进行了数值模拟 ,分析了改变样品参数对C V特性的影响 .利用改变极化电荷、n AlGaN层掺杂浓度和肖特基势垒高度对C V曲线不同部分位置和形状影响不同 ,可以精确地求取极化电荷面密度 .通过模拟 ,得到Al0 2 2 Ga0 78N厚度为 45nm的调制掺杂Al0 2 2 Ga0 78N GaN异质结界面附近极化电荷面密度为 6 78× 10 1 2 cm- 2 .Polarization-induced charge density in modulation-doped Al xGa 1-x N/GaN heterostructures is extracted through the simulation of the Schottky Capacitance-Voltage (C-V) characteristics. C-V measurements were made on Pt Schottky contacts on modulation-doped Al {0.22}Ga {0.78}N/GaN heterostructures. The C-V characteristics were simulated numerically using the three-dimensional Fermi model.Influence of sample parameters on C-V characteristics is analized by the simulation.Polarization-induced charge density,n-AlGaN doping level and Schottky barrier height have different influences on the C-V characteristics,and thus the polarization-induced charge density can be extracted accurately.The polarization-induced sheet charge density at the heterointerface is extracted to be 6.78×10 12 cm -2 in the Al 0.22 Ga 0.78 N/GaN heterostructure with the Al 0.22 Ga 0.78 N thickness of 45nm.This work provides a method for quantitative analysis of the polarization-indeced charge in modulation-doped Al xGa 1-x N/GaN heterostructures.

关 键 词：AlxGa1-xN/GaN异质结 极化电荷 肖特基电容-电压特性 数值模拟 三维费米模型 场效应晶体管 调制掺杂 

分 类 号：TN32[电子电信—物理电子学]