Formation of polymers in TMGa/NH3/H2 system under GaN growth

We report analysis of gas-phase chemistry and the generation pathways of polymers in a horizontal reactor under metalorganic vapor-phase epitaxy of GaN films by using computational fluid dynamics simulations. The simulation model considered radiative heat transfer and the reaction model of TMGa/NH3/H2 system, including the formation of polymers such as [Ga–N]n and [MMGaNH]n (n=2–6). It was found that Ga–N polymers are generated at a temperature region about 700 K, and that the temperature is the boundary between [Ga–N]2 dissociation ([Ga–N]2→Ga–N) and Ga–N polymerization (such as [Ga–N]2→[Ga–N]3–6).