用逆压电极化模型对AlGaN/GaN高电子迁移率晶体管电流崩塌现象的研究  

Research on the current collapse in AlGaN/GaN high-electron-mobility transistors through the inverse piezoelectric polarization model

作　　者：李若凡[1] 杨瑞霞[1] 武一宾[2] 张志国[2] 许娜颖[1] 马永强[1] 

机构地区：[1]河北工业大学信息工程学院,天津300130 [2]中国电子科技集团公司第十三研究所,石家庄050051

出　　处：《物理学报》2008年第4期2450-2455,共6页Acta Physica Sinica

基　　金：国家重点基础研究发展规划(批准号:51327030402);天津市自然科学基金(批准号:07JCZDJC06100)资助的课题~~

摘　　要：通过自洽求解一维Poisson-Schrdinger方程,模拟了AlGaN/GaN高电子迁移率晶体管在工作时等效外电场对AlGaN/GaN异质结沟道处二维电子气(2DEG)浓度的影响.分析了逆压电极化效应的作用,从正-逆压电极化现象出发,提出了逆压电极化模型.计算结果显示:逆压电极化明显影响2DEG性质,当Al组分x=0.3,AlGaN层厚度为20nm时,不考虑逆压电极化,2DEG浓度为1.53×1013cm-2;当等效外电压分别为10和15V时,2DEG浓度降低至1.04×1013cm-2和0.789×1013cm-2.用该模型解释了2DEG退化及电流崩塌现象产生的原因,并讨论了抑制电流崩塌的办法.Current collapse in AlGaN/GaN high-electron-mobility transistors was studied and the effect of effective external electrical field on the concentration of two-dimensional electron gas （2DEG） near the channel of hetero-junction of AlGaN/GaN was simulated through the self-consistent implementation of the one-dimensional Poisson-Schrodinger equations. An inverse piezoelectric polarization model was proposed to analyze the degradation of 2DEG and the current collapse. It was found that the density of 2DEG was strongly dependent on the inverse polarization. When the voltage was 0,10 and 15 V, the density was 1.53 × 10^13 cm^-2 , 1.04 × 10^13 cm^-2 and 0.789 × 10^13cm^-2 , respectively. It was clear that the 2DEG density dropped 48.4% with voltage increasing from 0 to 15 V when the inverse piezoelectric polarization was considered. At last, the method of restraining current collapse was further discussed.

关 键 词：ALGAN/GAN高电子迁移率晶体管 Poisson-Schrodinger方程 逆压电极化模型 电流崩塌 

分 类 号：O472[理学—半导体物理]