This paper reports, for the first time, a novel three-flow six-wafer reactor that can be developed for a metal-organic chemical vapor deposition (MOCVD) system to grow GaN-based structures. Two parallel gas-flows for a group-III source and ammonia (NH3) are separated by a quartz plate which is also parallel to the substrate. Nitrogen (N-2), which is used as sub-flow, flows through a quartz filter perpendicular to the substrate where it meets the two parallel group III and group V source flows. This new flow arrangement enhances the mixture of group III-V sources at the contacting substrate. Six 2-in substrates, one at the center and the others in the area surrounding that at the center, can be loaded at one time. In order to obtain high quality and good uniformity, these substrates are spun and rotated by a gear system. Based on this MOCVD system with this configuration, a mirror-like epitaxial GaN layer on sapphire substrate is obtained. The thickness uniformity within one wafer and wafer to wafer are <4%, thus demonstrating good uniformity. Also, the quality of the GaN layers are characterized by room-temperature photoluminescence, X-ray diffraction measurements, and Hall measurement. (C) 2002 Elsevier Science B.V. All rights reserved.