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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。
An AlGaN / Al Na / GaN / Al Nb / GaN HEMT structure with double Al N insertion layer was designed to improve the channel’s limitation on 2DEG and improve the electrical properties of the material. The structure was grown by MOCVD, and the influence of the growth time of the first AlNb interlayers on the surface morphology and electrical properties of the material was studied. The optimum AlNb growth time was between 15-20 s. The temperature-dependent Hall test was carried out on samples with AlNb growing time of 15s. The 2DEG mobility was 8849cm2 / Vs at 80K and 1967cm2 / Vs at room temperature. The surface density remained about 1.02 × 1013cm-2 with almost no change with temperature . The square resistance value of this sample was 278.3Ω / □ and the nonuniformity was 1.95% measured by a non-contact square resistance test system. It is shown that the introduction of double AlN insertion layer has an obvious effect on improving the electrical properties of HEMT structure materials.