背势垒对InAlN/GaN异质结构中二维电子气的影响  

Influences of the Back Barrier on the Two-Dimensional Electron Gas in InAlN/GaN Heterostructures

作　　者：甘天胜 李毅[1] 刘斌[1] 孔月婵[2] 陈敦军[1] 谢自力[1] 修向前[1] 陈鹏[1] 陈辰[2] 韩平[1] 张荣[1] 

机构地区：[1]南京大学电子科学与工程学院,南京210093 [2]南京电子器件研究所微波毫米波单片集成和模块电路重点实验室,南京210016

出　　处：《微纳电子技术》2014年第6期359-365,共7页Micronanoelectronic Technology

基　　金：国家重点基础研究发展计划(973计划)资助项目(2011CB301900;2012CB619304);国家高技术研究发展计划(863计划)资助项目(2011AA03A103);国家自然科学基金资助项目(60990311;61274003;61176063);新世纪优秀人才支持计划资助项目(NCET-11-0229);江苏省自然科学基金资助项目(BK2011010;BY201377;BK2010385;BE2011132);重点实验室基金资助项目(9140C140102120C14);江苏省高校优势学科建设工程资助项目

摘　　要：利用有效质量理论自洽求解Poisson和Schrdinger方程理论研究了背势垒插入层对InAlN/GaN晶格匹配异质结构的电学性能的影响。研究表明,对于In0.17Al0.83N/AlN/GaN的异质结构,AlN的临界厚度为2.43 nm。此时,异质结中二维电子气(2DEG)浓度达到2.49×1013 cm-2,且不随势垒层厚度的变化而变化。重点模拟研究了具有背势垒的InAlN/AlN/GaN/AlGaN/GaN和InAlN/AlN/GaN/InGaN/GaN两种结构的能带结构和2DEG的分布情况。理论结果表明,采用AlGaN背势垒结构时,对于AlGaN的任意Al组分,GaN沟道层导带底能量均被抬升,增强了AlN/GaN三角势阱对2DEG的限制作用,提高了电子迁移率。采用InGaN/GaN作为背势垒结构,当InGaN厚度为2或3 nm时,三角势阱中的2DEG随InGaN中In组分的增加先升高后降低,这主要是由于GaN/InGaN界面处产生的正极化电荷的影响,引起电子在AlN/GaN三角势阱和InGaN/GaN势阱之间的分布变化。The effects of the back barrier insert layer on the electrical properties of InAlN/GaN lattice match heterostructures were researched by using the theory of effective mass self-consistent solution Poisson and Schrodinger equations. The research results show that the critical thickness of the AlN is 2.43 nm for In0.17Al0.83N/AlN/GaN heterostructure. The two-dimensional electron gas （2DEG） concentration reaches 2.49 × 10^13 cm^-2 in the heterostructure, which hardly changeswith the thickness of the barrier layer. The band structures and the 2DEG distributions in the InAlN/AlN/GaN/AlGaN/GaN and InAlN/AlN/GaN/InGaN/GaN heterostructures with the back barriers were simulated and researched. The theory results indicate that when AlGaN back barrier structure is adopted, the conduction band energy of the GaN channel is lifted up for any Al component in AIGaN, which enhances the restriction of AlN/GaN triangle potential well on 2DEG and improves the electronic mobility. By using InGaN/GaN as the back barrier structure, when the thickness of InGaN layer is 2 nm or 3 nm, the 2DEG in the triangle potential well increases at first and then decreases with the increase of In component in InGaN. The reason is that the effect of the positive polarization charge at the interface of GaN/InGaN causes the electron distribution change between AlN/GaN triangle potential wells and InGaN/GaN potential wells.

关 键 词：INALN GAN异质结构 背势垒插入层 二维电子气(2DEG) 能带结构 电子迁移率 

分 类 号：TN304.23[电子电信—物理电子学] O471.5[理学—半导体物理]