垂直转盘式MOCVD反应器进口温度对GaN生长的影响  

Effect of Inlet Temperature on Growth of GaN in a Vertical RDR MOCVD Reactor

作　　者：左然[1] 王宗琪[1] 陈鹏[2] 

机构地区：[1]江苏大学能源与动力工程学院,镇江212013 [2]南京大学电子科学与工程学院,南京210093

出　　处：《人工晶体学报》2015年第10期2778-2785,共8页Journal of Synthetic Crystals

基　　金：国家自然科学基金(61176009;61474058)

摘　　要：针对垂直转盘式MOCVD反应器进口温度对GaN生长的影响进行数值模拟研究,分别考虑预混合进口和分隔进口两种情况。通过对包含主要化学反应路径的气体输运过程的模拟,对比不同进口温度下衬底前沿的反应前体浓度及其对应的生长速率的变化,从而确定进口温度对化学反应路径及生长速率的影响关系。结果表明,两种进口情况下,随着进口温度的升高,生长速率均呈现先增大后减小的趋势。预混合时,进口温度约500K时生长速率最大;分隔进口时,进口温度约800K时生长速率最大。这主要是由于,生长速率取决于衬底上方边界层内含Ga粒子的浓度梯度。预混合时,衬底前沿的含Ga粒子主要为MMGa,其浓度随进口温度的变化趋势与生长速率的变化趋势一致。分隔进口时,衬底前沿的含Ga粒子MMGa和DMGaNH2浓度处于同一数量级。随进口温度的升高,前者略有增加,而后者明显增大。当预混合的进口温度超过500K、分隔进口的进口温度超过800K时,衬底前沿的MMGa和DMGaNH2的峰值或明显下降、或明显离开衬底,使得含Ga粒子的浓度梯度显著下降,造成生长速率下降。The effect of inlet temperature on GaN MOCVD growth in a rotating disk reactor was studied by numerical simulation, with both premixed and separated inlets. By solving the transport equations with major chemical reactions, and by comparisons of Ga-containing concentrations near the susceptor fi＇ont boundary and the corresponding growth rate, the effects of inlet temperature on chemical reactions and growth rate are determined. The results show that for both inlets, as the inlet temperature increasing, the growth rate first increases and then decreases. The maximum growth rates occur when temperature is 500 K for premixed inlet and 800 K for separated inlet. The main reason is that, the growth rate GR depends on the concentration gradient of Ga-containing gases near the susceptor front boundary. For the premixed inlet, the main Ga-eontaining gas is MMGa, whose concentration change with inlet temperature accords with that of growth rate. For the separated inlet, the concentrations of MMGa and DMGaNH2 are in the same magnitude in the susceptor front boundary. As the temperature increasing, the former increases a little and the latter increases greatly. When the inlet temperature is above 500 K for the premixed inlet and above 800 K for the separated inlet, either the concentrations of MMGa and DMGaNH2 decrease signifcantly, or the distance of the concentration peaks separate further apart from the susceptor, thus the concentration gradients of Ga-containing particles decrease and so does the growth rate.

关 键 词：MOCVD 进口温度 GAN 数值模拟 

分 类 号：TN304[电子电信—物理电子学]