Facet Formation In Selectively Overgrown Silicon By Reduced Pressure Chemical Vapor Deposition

Selective epitaxial growth (SEG) and epitaxial lateral overgrowth (ELO) of silicon have many applications in integrated circuit processing such as device isolation and self-aligned processes to enhance the integrated circuit performance as well as level of integration. However, in order for SEG to be applied for device fabrication, to the extent of production technology, reasonably high growth rate, high-quality epitaxial layers are prerequisite. Various facets were observed in the overgrown Si regions and it is known that the control of facet formation is important for subsequent device fabrication. (1 13) facets were primarily observed on (001) Si wafers, when SEG was made on Si window regions at high temperatures [1,2]. The mask patterns were along <110> direction. As SEG continued, some of SEG Si started to overgrow over the mask and (1 11) facets began to appear [2]. Recently, a (110) facet was reported in SEG silicon due to the stress induced at the overgrown silicon [3], however, the detailed mechanism for the (110) facet formation is not known.