In-Situ Ellipsometry and Light Scattering Studies of Substrate Cleaning and Initial Layer Deposition in Low Temperature CVD of Crystalline Si

Abstract
The first in-situ observations of initial stages of growth during Si vapour-phase homoepitaxy are reported, using the simultaneous measurement of dual-wavelength ellipsometry (364/488nm) and diffuse light scattering (488nm). Effective medium modelling shows that initial growth is nonuniform with pits present in the first 50–200Å of growth which rapidly fill in as growth proceeds. The sizes of the ellipsometric and scattering discontinuities are dependent on the extent of pre-growth roughening associated with oxide removal and finite wavelength effects become important for growth on roughened substrates.