Adsorption behavior of chemical contaminants by molecular simulation

The adsorption process of chemical contaminants on silicon wafers was investigated by using molecular mechanics, molecular dynamics, Monte Carlo method, and computer graphics. The adsorption energy of organic gaseous contaminants, such as DBP, DOP, and D5, on the hydrogen terminated silicon surface and its oxide surface, were estimated and compared. The adsorption energy of chemical contaminants was larger than that of low molecular weight species, such as benzene, H2O and NH3. The adsorption energy on the hydrogen terminated silicon surface was smaller than that on its oxide surface. The equilibrium adsorption amount on the silicon wafer was also calculated. It was indicated that the configuration of the adsorbed DBP molecules over its gas concentration of 1.9x103 ng/m3 showed multi-layer adsorption. It was indicated that adsorption energy and the equilibrium adsorption amount is a good index to estimate the adsorption properties of organic molecules.