AlGaN/AlN_a/GaN/AlN_b/GaN HEMT结构材料生长及性能表征

Growth and Characterization of AlGaN/AlN_a/GaN/AlN_b/GaN HEMT Structure Materials

设计了一种具有双Al N插入层的Al GaN/Al Na/GaN/Al Nb/GaN HEMT结构材料,用以提高沟道对2DEG的限制作用、改善材料的电学性能。采用MOCVD技术生长了该结构,重点研究了第一Al Nb插入层的生长时间对材料表面形貌和电学性能的影响,得到了最佳的Al Nb生长时间介于15~20s。对Al Nb生长时间为15s的样品进行了变温Hall测试,其2DEG迁移率在80K时达8849cm2/V.s,室温下为1967cm2/V.s,面密度始终保持在1.02×1013cm-2左右,几乎不随温度改变。用非接触式方块电阻测试系统测得该样品的方块电阻值为278.3Ω/□,不均匀性为1.95%,说明双Al N插入层的引入对提高HEMT结构材料的电学性能作用明显。

AlGaN/AlNa/GaN/AlNb/GaN HEMT structure with two AlN interlayers was designed to enhance two-dimensional electron gas(2DEG)confinement and improve electrical property.The structure was grown by MOCVD and the influence of AlNb growth time was stu-died.The optimized growth time is 15 to 22 s.Temperature dependent Hall measurement shows that the mobility is 8 849 cm2/V·s at 88 K and 1 967 cm2/V·s at room temperature with a nearly constant sheet carrier density of 1.02×1013 cm-2.Sheet resistance measured by Lehighton contactless measurement system is 278.3 Ω/□ with a un-uniformity of 1.95%,which indicates that electrical property is improved obviously by the double interlayer.