蓝宝石衬底异质外延碳化硅薄膜反应机理研究

对宽禁带半导体材料碳化硅薄膜的异质外延工艺和反应机理进行了讨论，针对实验使用常压水平卧式反应室，分析了生长过程中气流流速分布、反应室内温度分布以及反应气体浓度分布，指出“汽相结晶”过程对薄膜生长区Si/C比例有很大影响，从而影响了碳化硅薄膜的生长速率，在SiC薄膜的生长过程中，对Si/C原子比例的控制一直是影响薄膜表面形貌和膜层掺杂浓度的重要因素。这很好地解释了薄膜生长过程中出现的异常现象。

Mechanism of SiC heteroepitaxy on sapphire by APCVD

Single-crystal silicon carbide film were grown on sapphire substrate with a Nitride buffer-layer using APCVD (Atmospheric Pressure Chemical Vapor Deposition). Silicon-v apor crystallizationprocess was discussed. It is known that a reliable control of transport of Si-and C-containing speciesto the growth region and C/Si ratio over the wafer surface is of crucial impor tance to surface morphologyand doping level of SiC epitaxial layer. The results show that gas phase cryst allization of Si-droplets are critical to control the C/Si ratio over the growing region. A simple set o f chemical reactions is pro-vided to simulate precursors and gas spices distribution in quartz tube. SEM o bservation also verifysthat silicon-vapor crystallization and surface absorption of Si-droplet do o ccur in growing process ofSiC. Gas phase crystallization of Si-droplets also give a good explanation to the relations between epi-layer growth rate and precursors' flow rate.