Unintentional gallium incorporation in AlN and its impact on the electrical properties of GaN/AlN and GaN/AlN/AlGaN heterostructures
Unintentional gallium incorporation in AlN and its impact on the electrical properties of GaN/AlN and GaN/AlN/AlGaN heterostructures
复制标题
DOI：
10.1088/0268-1242/30/5/055015
复制
发表时间：
2015-05
影响因子：
1.9
通讯作者：
Haoran Li;S. Keller;Silvia H. Chan;Jing Lu;S. Denbaars;U. Mishra
中科院分区：
文献类型：
--
作者：
Haoran Li;S. Keller;Silvia H. Chan;Jing Lu;S. Denbaars;U. Mishra
薄AlN中间层被广泛应用于(In，Al，Ga)N基高电子迁移率晶体管中，以改善在GaN/(In，Al，Ga)N界面形成的二维电子气的迁移率。然而，通过金属-有机化学气相沉积生长的AlN层最近被证明含有大量的Ga，这是由于遗留反应导致的，导致在典型的沉积条件下，AlxGa1−xN层的x∼为0.5.通过改变本研究中的AlN生长条件，获得了Al摩尔分数高达0.78的膜层。无意识的Ga掺杂对GaN/AlN/AlGaN结构的电子性质的影响可以忽略不计，GaN过渡层厚度为0.7 nm，片状载流子密度约为1×10~(13)cm−-3。然而，对于名义上较厚的AlN层和/或较高的片状载流子密度，这会导致较低的电子迁移率。
Thin AlN interlayers are widely used in (In,Al,Ga)N based high-electron-mobility transistors to improve the mobility of the two-dimensional electron gas forming at the GaN/(In,Al,Ga)N interface. AlN layers grown by metal-organic chemical vapor deposition, however, were recently shown to contain high amounts of gallium caused by carry over reactions, resulting in AlxGa1−xN layers with x ∼ 0.5 under typical deposition conditions. By modifying the AlN growth conditions in this study, layers with an Al mole fraction up to 0.78 were obtained. The unintentional Ga incorporation had a negligible effect on the electronic properties of GaN/AlN/AlGaN structures with nominally 0.7 nm thick AlN interlayer and sheet carrier densities in the order of 1 × 1013 cm−3. It resulted, however, in low electron mobility values for samples with thicker nominal AlN layers and/or higher sheet carrier densities.