3-D atomistic kinetic Monte Carlo simulations of point defect incorporation during CVD diamond film growth

Abstract

The incorporation of vacancies and H atoms into {100}- and {111}-oriented diamond films during CVD growth in an atmosphere of H, H2, CH3, and C2H2 is simulated atomistically. The growing films are represented in three dimensions by a diamond cubic lattice, and the temporal evolution of the surfaces is accomplished by a kinetic Monte Carlo method. The dimer bonding of diamond atoms on the {100} surface is treated explicitly. Growth begins on {100}(2×1):H and {111}:H surfaces containing 288 and 300 atoms, respectively, in the surface plane, and the growth of approximately sixty atomic layers (18,000 atoms) is accomplished at each of fifteen substrate temperatures between 800 and 1500 K. The growth rates depend on the combined contributions to growth from CH3 and C2H2, whereas the point defect concentrations depend on the ratio of C2H2 to CH3 growth. The maximum {100} growth rate is achieved at approximately 1200 K. Point defect concentrations are low at temperatures below 1300 K, but become high above 1300 K. Growth efficiency, defined as the ratio of growth rate to defect concentration, is maximum for both film orientations at substrate temperatures in the vicinity of 1100 to 1200 K.