Low temperature selective Si epitaxy by reduced pressure chemical vapor deposition introducing periodic deposition and etching cycles with SiH₄, H₂ and HCl

This paper presents the experimental results of selective Si epitaxial growth from 650 °C to 700 °C on (100) silicon wafers with oxide patterns using reduced pressure chemical vapor deposition with the SiH₄-HCl-H₂ gas system. In addition, an HCl etching process is introduced and the conditions of the deposition and etching processes are addressed to sustain the selectivity. As a result, we noted that the addition of HCl serves not only to reduce the growth rate on bare Si, but also to suppress the nucleation on SiO₂. In these experiments it has been also observed that the Si layer was grown to 3 nm while sustaining the selectivity. Moreover, further introduction of the HCl etching process following the deposition allowed a 50 nm-thick film to sustain the selectivity for twenty periods.