Atmospheric photoassisted chemical vapor deposition of Si using ultraviolet-light irradiated H₂ carrier gas and nonexcited SiH ₂Cl₂

We have proposed a new photoassisted chemical vapor deposition (photo-CVD) process of Si, in which only a hydrogen carrier gas is excited by UV light from low-pressure Hg lamps and a reactant gas of SiH₂Cl₂ is not irradiated at all. In this type of photo-CVD, it is found that (1) the number of pyramidal hillocks on orientation-just surfaces is drastically suppressed, (2) the number of etch pits, corresponding to the stacking fault and the precipitation of contaminants, is also decreased, (3) the growth rate is significantly enhanced, and (4) the surface roughness is decreased. In particular it should be emphasized that these effects are more apparent at atmospheric pressure. It is suggested that the UV-light irradiated hydrogen plays an important role in removing chlorine atoms adsorbed on the surface.