Characterization of InN Grown Directly on Sapphire Substrate Using Plasma-Enhanced Metal Organic Chemical Vapor Deposition

Direct InN growth is demonstrated and characterized on a sapphire (Al2O3) substrate by plasma-enhanced metal-organic chemical vapor deposition using high-density nitrogen (N-2) microstrip-line microwave plasma. N-2 plasma irradiation at 650 degrees C for 20 min forms AlN on Al2O3 substrate. No peak regarding metallic In droplets is detected from InN/Al2O3 regardless of N-2 plasma irradiation. InN is found to be rotated 30 degrees with their a-axis oriented to become [10 (1) over bar0] InN // [11 (2) over bar0] Al2O3. The transition layers are confirmed at the InN/Al2O3 interface regardless of N-2 plasma irradiation. The surface of InN consisted of large undulations with root mean square values >30 nm, suggesting that strain relaxation introduces misfit dislocations.