We fabricated high-electron-mobility transistor structures with InAlN as a barrier layer on 8- or 6-inch Si substrates by using a recently developed high-speed-wafer-rotation single-wafer MOCVD tool. It has been reported that Ga inclusion in the InAlN layer causes serious problems in the control of group III metal composition in some cases, but the samples grown using the tool exhibited an InAlN layer with an abrupt interface and almost no Ga inclusion. Excellent in-wafer uniformity, repeatability, and wafer-to-wafer uniformity of device structure are also reported. The results shown in this paper indicate high performance of the tool in the real production of devices.