Selective etching and epitaxial refilling of silicon wells in the system SiH 4/HCl/H 2

Abstract

Wells were etched in (100) silicon by different kinds of selective etching and were selectively refilled by using different gas systems. Masking materials were SiO 2 and Si 3N 4; for the refilling the systems SiCl 4/H 2 and SiH 4/HCl/H 2 were studied. By using a combination of weak anisotropic gas etching with HCl (Si 3N 4 films as mask) and of SiH 4/HCl/H 2 as refilling system, plane surfaces without ridges at the boundary of the mask and without nuclei on the mask were reached. The results were obtained by SEM, light microscopic and profile investigations and are compared with the other kinds of etching and refilling.