A new three-layer hot-wall horizontal flow metal-organic chemical vapor deposition （MOCVD） reactor is proposed. When the susceptor is heated, the temperature of the wall over the susceptor also increases to the same temperature. Furthermore, the flowing speed of the top layer is also increased by up to four times that of the bottom layer. Both methods effectively decrease the convection and make most of the metal organic （MO） gas and the reactive gas distribute at the bottom surface of the reactor. By selecting appropriate shapes, sizes, nozzles array, and heating area of the walls, the source gases are kept in a laminar flow state. Results of the numeric simulation indicate that the nitrogen is a good carrier to reduce the diffusion among the precursors before arriving at the substrate, which leads to the reduction ofpre-reaction. To get a good comparison with the conventional MOCVD horizontal reactor, the two-layer horizontal MOCVD reactor is also investigated. The results indicate that a two- layer reactor cannot control the gas flow effectively when its size and shape are the same as that of the three-layer reactor, so that the concentration distributions of the source gases in the susceptor surface are much more uniform in the new design than those in the conventional one.
