表面预处理对SiO2/Si结构上APCVD生长SiC薄膜的影响

采用S iH4-C3H8-H2气体反应体系在S iO2/S i复合衬底上进行了S iC薄膜的APCVD生长。实验结果表明,H2表面预处理温度过高或时间过长会导致衬底表面S iO2层熔化再结晶或被腐蚀掉。通过“先硅化再碳化”的工艺方法可以较好地解决S iO2/S i复合衬底上S iC成核困难以及粘附性差的问题,同时还可以有效抑制S iO2中的O原子向S iC生长膜扩散。选择预处理温度和薄膜生长温度为1180℃、H2预处理、S iH4硅化和C3H8碳化时间均为30 s的最佳生长条件时,可以得到<111>晶向择优生长的多晶3C-S iC外延薄膜,薄膜生长速率约为2.0~2.5nm/m in.

Influences of Surface Pretreatment on SiC Films Grown by Atmospheric Pressure Chemical Vapor Deposition Process on SiO2/Si Structures

SiC thin films were grown on SiO2/Si structures via atmospheric pressure chemical vapor deposition (APCVD) process with SiH4-C3H8-H2 reaction system. Experimental results show that the SiO2 layer on the Si substrates can be melted and reconstructed or removed completely by H2 when the surface pretreatment temperature is too high or the pretreatment time is too long. A special process named "silicification followed by carbonization" was adopted to solve the problems such as SiC grains forming on the SiO2 and poor cohesiveness between the SiC and substrate. Furthermore,this method is effective to prevent O atoms diffusing from SiO2 into SiC epilayer. Polycrystal cubic SiC (3C-SiC) films of the preferential orientation grown along < 111 > direction can be obtained under an optimum process condition such as 1180℃, H2 pretreatment, silicification and carbonization time of all 30s,where the growth rate of SiC films is about 2.0-2.5 nm/min.