APCVD生长碳化硅薄膜中汽相结晶过程的研究

INFLUENCE OF SILICON-VAPOR NUCLEATION ON SILICON CARBIDE FILM GROWTH USING APCVD

对宽禁带半导体材料碳化硅薄膜的常压化学汽相沉积 ( APCVD)异质外延技术进行了讨论 .在 Si C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 .针对水平卧式反应室 ,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 。

Single crystal silicon carbide film growing on sapphire substrate with a Nitride buffer layer using APCVD(Atmospheric Pressure Chemical Vapor Deposition) is discussed with emphasis on silicon vapor nucleation process.It has been known that a reliable control of transport of Si and C containing species to the growth region and C/Si ratio over the wafer surface is of crucial importance to surface morphology and doping level of SiC epitaxial layer.In this paper it has been shown that gas phase nucleation of Si droplets are critical to control the C/Si ratio over the growing region.A simple set of chemical reactions is provided to simulate precursors and gas spices distribution in quartz tube.A SEM imagine also verify that silicon vapor nucleation and surface absorption of Si droplet do occur in growing process of SiC.Gas phase nucleations of Si droplets also give a good explanation to relations between epilayer growth rate and precursors′s flow rate.