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 vaporphase epitaxy of GaN films by using computational fluid dynamics simulations. The simulation model considered radiative heat transfer and the reaction model of TMGa/NH3/H-2 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)). (c) 2006 Elsevier B.V. All rights reserved.