Transport phenomena and chemical reactions relating to silicon epitaxial thin film growth at 1073-1398 It in a SiHCl3-H-2 system with dopant gas of B2H6 under atmospheric pressure are studied theoretically and experimentally for a cold-wall horizontal single-wafer reactor. The effects of substrate rotation and thermal diffusion on SiHCl3 gas and B2H6 gas are discussed. The nonlinear increase in silicon epitaxial growth rate with SiHCl3 concentration at the inlet of the reactor is discussed by investigating changes in the transport of the chemical species to the substrate surface, and the saturation of chemisorbed species at the surface. Indicators for the rate limiting factor for species transport and reaction are discussed to investigate the saturation of the epitaxial growth rate, and are shown to be effective for quantitatively describing the rate limiting process. Various phenomena to be modeled in epitaxy are also addressed.