论文部分内容阅读
通过自洽求解薛定谔方程和泊松方程,较系统地研究了GaN沟道层、AlGaN背势垒层、Si掺杂和AlN插入层对N极性GaN/AlGaN异质结中二维电子气(2DEG)的影响,分析表明,GaN沟道层厚度、AlGaN背势垒层厚度及Al组分变大都能一定程度上提高二维电子气面密度,AlGaN背势垒层的厚度和Al组分变大也可提高二维电子气限阈性,且不同的Si掺杂形式对二维电子气的影响也有差异,而AlN插入层在提高器件二维电子气面密度、限阈性等方面表现都较为突出,在模拟中GaN沟道层厚度小于5nm时无法形成二维电子气,超过20nm后二维电子气面密度趋于饱和,而AlGaN背势垒厚度超过40nm后二维电子气也有饱和趋势,对均匀掺杂和delta掺杂而言AlGaN背势垒层Si掺杂浓度超过5×10~(19)cm~(-3)后2DEG面密度开始饱和,而厚度为2nmAlN插入层的引入会使2DEG面密度从无AlN插入层时的0.93×10~(13)cm~(-2)提高到1.17×10~(13)cm~(-2)。
The self-consistent solutions of Schrödinger equation and Poisson’s equation are used to systematically study the effects of GaN channel layer, AlGaN back barrier layer, Si doping and AlN insertion layer on the 2DEG ). The results show that the thickness of the GaN channel layer, the thickness of the AlGaN back barrier layer and the Al composition increase to a certain extent, and the two-dimensional electron gas surface density is increased. The thickness of the AlGaN back barrier layer and the Al composition become larger But also the threshold of two-dimensional electron gas is increased, and the influence of different Si doping forms on the two-dimensional electron gas is also different. However, the performance of the AlN insertion layer in improving the two-dimensional electron gas density and threshold of the device is relatively high , The two-dimensional electron gas can not be formed when the thickness of the GaN channel layer is less than 5 nm in simulation, and the two-dimensional electron gas density becomes more saturated when the thickness exceeds 20 nm. However, the two-dimensional electron gas also has a tendency of saturation after the thickness of the back barrier reaches more than 40 nm, For uniform doping and delta doping, the 2DEG surface density of AlGaN back barrier reaches more than 5 × 10 ~ (19) cm ~ (-3), and the introduction of 2nm AlN insertion layer will make The surface density of 2DEG increased from 0.93 × 10 ~ (13) cm ~ (-2) to 1.17 × 10 ~ (13) cm ~ 2 without AlN insertion layer.