Homoepitaxial GaN growth was implemented, studied, and improved in a production scale MOCVD reactor. The epitaxial GaN threading dislocation density was very close to that of the different free-standing GaN substrates and uniform across large diameters. We were able to limit incorporation of impurities to the low levels required for vertical electron drift layers by using appropriate growth process conditions. Different surface analysis studies revealed near-perfect step flow growth over large areas of the wafers.