Robust selective-epitaxial-growth process for hybrid SOI wafer

Robustness of the selective-epitaxial-growth process of silicon was demonstrated for the first time. Process margin of selectivity was investigated quantitatively. The number of the silicon nuclei on dielectric layer and the growth rate of the selective epitaxial layer were studied by using Taguchi Method. 8 process parameters were selected as control factors in this study, and 6 process parameters influenced the silicon nucleation and 5 process parameters of them influenced the growth rate of selective epitaxial layer. With calculating the number of the silicon nuclei that could not be detected by available measurement method, the difference of the process margin of the selectivity could be determined. Also, it was cleared that the most effective process parameter for suppression of silicon nucleation was the flow rate of SiH₂Cl₂.