Tungsten carbide (WC) has been suggested as a new buffer layer for the GaN-on-Si technology. We have investigated and optimized the sputtering condition of WC layer on the Si-substrate. We confirmed the suppression of the Si melt-back phenomenon. In addition, surface energy of WC/Si layer was measured to confirm the possibility as a buffer layer for GaN growth. We found that the surface energy(γ=82.46 mJ/cm2) of WC layer is very similar to that of sapphire substrate(γ=82.71 mJ/cm2). We grow GaN layer on the WC buffer by using gas-source MBE, and confirm that it is available to grow a single crystalline GaN layer.
