SYSTEMATIC APPROACH TO CONTROLLING ABNORMAL STRUCTURES GROWTH IN CVD - SIMULATION OF NODULE STRUCTURE EVOLUTION -

摘要

To investigate the growth mechanism of nodule structure during CVD, two-dimensional mesh model based simulators for solid growth were prepared. In the simulator for growth under molecular flow regime, trajectories of each deposition species are traced by Monte-Cairo method. For viscous flow regime, diffusion equation of deposition species is solved to get deposition profile along the solid surface. Assuming that the cause of nodule structure is evolution of irregularities on the substrate during growth, growth simulations on the substrate with a protuberance were examined. In molecular flow regime, growth under the conditions with long mean free path length of deposition species, 1, results no evolution of irregularities even for the deposition species with high sticking probability. For the condition with small A, the irregularities tends to expand during deposition to form nodule like growth. Simulation of deposition under viscous flow regime corresponds to extremely small λ and irregularities expand even for small sticking probabilities.