Papers by Keyword: KMC Simulation

Abstract: The growth of nano CVD diamond films on low index faces such as (111) face and (100) face under different proposed surface chemical reaction model was simulated by using Kinetic Monte Carlo (KMC) method from atomic scale. The results, for example the influence of deposition time t, substrate temperature T_s, and atomic hydrogen concentration [H] on the film deposition rate, surface roughness, and H embedded in the film under different processing conditions, were systematically analyzed and compared. And the adsorption of various species on {111}-oriented diamond cluster was preliminarily computed from electronic scale by Local Density Approximation (LDA) method to assist understanding the surface adsorption mechanism. It is indicated that the film morphology and quality obtained from atomic scale KMC simulation varies according to the chemical reaction models. And our initial electronic scale computation on {111}-oriented diamond cluster showed that single-carbon species can be adsorbed on the activated site more easily than double-carbon species and the former will result in a more stable state than the latter. In order to reveal the nano CVD diamond film growth mechanism, more work about various species adsorption on many different morphological CVD diamond surfaces is needed.

Abstract: A 2D kinetic Monte Carlo (KMC) simulation has been applied to study the microstructure of Ni-Cr film deposited by physical vapor deposition (PVD) for variable incident angle. In the KMC method, two phenomena were incorporated: adatom-surface collision and adatom diffusion, the interaction between atoms was described by embedded atom method and jumping energy was calculated by molecular statics calculations, initial location of adatom was located by Momentum Scheme. The results reveal that there exists critical incident angle, which is 35˚ for Ni-Cr thin film. When incident angle is less than 35˚, incident angle have less affect on surface roughness factor and packing density, compact films with smooth surface are obtained, their surface roughness factor is bellow 1.12 and packing density is more than 99.6%. However, when incident angle is more than 35˚, surface roughness factor increases quickly and packing density decreases sharply with incident angle increasing: surface roughness factor increase to 1.5 and 2.3 for incident angle of 45˚ and 60˚ respectively, packing density is below 99% and 96% accordingly. Which reveal that the self-shadowing effect emphasizes with incident angle increasing when the incident angle is more than 35˚.