Effects of polycrystalline AlN layer on the crystalline quality of AlxGa1-xN buffer layer and optimization of growth processes: A molecular dynamics study

YF Song and R Li and CM Cheng and G Wu and W Shen and XM Liu and DW Wu and K Liang and S Liu, MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, 188, 109263 (2025).

DOI: 10.1016/j.mssp.2024.109263

GaN-on-diamond power devices exhibit superior thermal performance due to the exceptional thermal conductivity of diamond. Enhancing GaN film quality on diamond involves first depositing an AlN seed layer on (111) single-crystal diamond (SCD) substrates via magnetron sputtering, followed by AlxGa1-xN buffer layer growth. However, the influence of polycrystalline AlN (Poly-AlN) layers on the atomic-scale crystalline quality of AlxGa1xN remains underexplored. This study employs molecular dynamics (MD) simulations to investigate the deposition of AlxGa1-xN on Poly-AlN seed layers with varying grain sizes and AlN mole fraction. Results indicate that larger grain sizes reduce grain boundaries, enhancing the crystalline quality of the buffer layer. Additionally, a lower AlN mole fraction increases the lattice constant of AlxGa1-xN, thereby increasing the lattice mismatch with AlN. Post-annealing simulations reveal a reduction in mean biaxial stress by over 50 % and a decrease in average normal stress in the Z direction by more than 35 % in the final equilibrium state.

Return to Publications page