Method of producing a SiO2 layer on a single crystalline silicon body

摘要

A layer of SiO2 is produced on the surface of a monocrystalline Si body by first subjecting the body to the action of a gaseous reactant to remove a surface layer of Si, then rinsing with an inert gas, and oxidizing the Si surface with O2 or H2O vapour. The gaseous reactant may be a halogen or a hydrogen halide, e.g. HCL, and may be diluted with H2 or Ar. The removal of the Si layer may be effected by a transport reaction between the Si surface and the adjacent surface of a parallel cover-plate spaced at a distance of 0.1-1 mm. away and maintained at a temperature 15-30 DEG C. lower than the Si body. In this case, a halogen compound of Si, e.g. SiCl4 or SiHCl3 may be used, preferably mixed with H2 in the ratio 0.01 : 1 to 0.05 : 1; it decomposes in the hot parts of the vessel to deposit Si and form HCl, which then acts as the transport gas. The cover-plate may be made of Si, or quartz, SiC, or graphite, which may be coated with Si. It may rest on the Si body, be separated by a spacer, or be arranged freely, and is preferably removed before oxidation. A plurality of Si bodies may be treated by using a single cover-plate with slots between the bodies, or by stacking the bodies vertically so that each acts as a cover-plate for the next. The inert rinsing gas may be N2, H2 or a rare gas, e.g. Ar. The water vapour oxidant may be carried by H2 or a rare gas. The temperature of the Si body may be 1100-1250 DEG C. during etching, 1150-1200 DEG C. during rinsing, and 900-1150 DEG C. during oxidation. A continuous flow or closed system may be used.