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

ABSTRACTThis 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.