Abstract：Ga N films were deposited on freestanding diamond substrate by electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition (ECR-PEMOCVD) technique with various buffer layer deposition temperature. The effect of buffer layer deposition temperature on the quality of Ga N flim was studied using reflection high energy electron diffraction (RHEED) , X-ray diffraction (XRD) and atomic force microscope (AFM) . The results show that Ga N film deposited with buffer layer is very important, and as-grown Ga N films is of high c-axis preferred orientation and highly crystallined with the buffer layer temperature deposited at 100 ℃, and the Ga N fims have the smooth surface.

Keywords：ECR-PEMOCVD system; GaN films; freestanding diamond substrate; buffer layer deposition temperature