High Temperature Chemical Vapor Deposition advantages

An additional advantage of molecular beam epitaxy over chemical vapor deposition is that lower substrate temperatures are used in molecular beam epitaxy. The high temperatures required to effect a chemical reaction in chemical vapor deposition are not needed in molecular beam epitaxy. Given the extremely thin nature of the films, atomic diffusion is kept to small distances, and hence the small diffusion coefficients do not seriously retard the overall reaction rate. The difficulty presented by small diffusion coefficients with respect to chemical reactions between bulk solids is discussed in Chapter 5. 

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