Publications
LDRD 191204: Optimization of Sputtered Aluminum Nitride for the Seeding of Metal Organic Chemical Vapor Deposition Gallium Nitride Films
GaN-on-Si combines the wide bandgap advantages of GaN with the cost and scaling advantages of Si. Sputtered A1N is an attractive nucleation layer material because it reduces Al diffusion into the Si and eliminates a time-intensive preconditioning step in the GaN growth process, but is limited by the poor film quality of PVD A1N films deposited on Si substrates. Sputtering also offers a large degree of control over A1N film properties, including control of the intrinsic stress using substrate biasing. Doping the A1N films with Sc improves the lattice match to A1GaN and GaN films by expanding the a-axis and c-axis lattice parameters. A1N and A10.88Sc0.12N films have been grown on silicon, metal, and sapphire substrates and characterized for properties such as stress, grain size, roughness, and film orientation for use as nucleation layers for MOCVD GaN growth.