Silicon oxidation in wet ambients is simulated based on the interfacial silicon emission model and is compared with dry oxidation in terms of the silicon-atom emission. The silicon emission model enables the simulation of wet oxidation to be done using the oxidant self-diffusivity in the oxide with a single activation energy. The amount of silicon emission from the interface during wet oxidation is smaller than that during dry oxidation. The small emission rate for wet oxidation is responsible for the insignificant initial oxidation enhancement and the linear pressure dependence of the oxidation rate observed in wet oxidation. Using a unified set of parameters, the whole range of oxide thickness is fitted for both (100) and (111) substrates...