In this paper, an HCl-free silicon selective epitaxy process is presented. The low pressure chemical vapor deposition (LPCVD) process uses a mixture of silane and dichlorosilane in hydrogen. The selective growth conditions are established by varying the growth temperature and the proportion of dichlorosilane in the gas mixture. Highly selective silicon epitaxial layers with smooth morphology are obtained within a wide range of growth temperatures. No apparent local loading effect is observed. The use of both DCS and silane provides a means to adjust the silicon growth rate by allowing independent control of the etching component (dichlorosilane) and the growth component (silane). The independent control of etching and growth components of the overall chemistry makes it possible to increase the silicon on oxide incubation period, allowing the fabrication of devices where long epitaxial growth times are needed.
- low pressure chemical vapor deposition
- selective epitaxial growth
- surface morphology