SiC单晶生长热力学和动力学的研究

升华法生长大直径碳化硅(SiC)单晶一直是近年来国内外研究的重点,本文对Si-C系中的Si,Si2,Si3,C,C2,C3,C4,C5,SiC,Si2C,SiC2等气相物种的热力学平衡过程进行了研究,发现SiC生长体系中的主要物种为Si,Si2C,SiC2.生长初期Si的分压较高,从而SiC生长为富硅生长模式.对外加气体进行研究发现,氩气为最好的外加气体,它既可以有效地抑制Si物质流传输,又可以减缓扩散系数随温度升高而递减的趋势.建立了简单一维传输模型,对三个主要物种的动力学输运过程进行了研究,计算得到了两个温度梯度下的主要物种的物质流密度.

Investigation on the Thermodynamics and Kinetics of the Growth of SiC Single Crystal

Much attention focused on the growth of silicon carbide (SiC) single crystal with large diameter in recent years. The thermodynamics equilibrium process of Si,Si_2,Si_3,C,C_2,C_3,C_4,C_5, SiC,Si_2C,SiC_2 was analyzed. It was found that the Si, Si_2C, SiC_2 are the main reactants. The partial pressure of silicon vapor is higher than that of other reactants, so the growth of SiC is Si-rich growth at the first growth stage. It was also found that the Ar can slow down effectively the transport of silicon vapor and reduce the decrease tendency of diffusion coefficient with the increase of tempreture. We built a one-dimensional transport model and calculated flux density of the main reactants at two kinds of temperature gradients.