A theoretical study of laser-induced chemical vapor deposition

The laser-induced chemical vapor deposition process has been studied using a Monte Carlo procedure. First the action of the laser beam is assumed to induce the gas-phase decomposition of a parent organometallic molecule. It was then assumed that pyrolytic decomposition of adsorbed species can be neglected. The goal of the simulations was to establish the relationship between the morphology of the deposited layer as well as the deposition rate and various characteristics of the system. In particular the dependence on buffer gas pressure, beam intensity and nature (continuous and pulsed) and beam shape were examined. It was found that when a CW beam is used "volcano"-shape deposited layers are obtained due to a competition between the diffusion of parent organometallic molecules back into the irradiated zone and the rate of photodissociation fragments production. In contrast, Gaussian-shape deposited layers were obtained for a pulsed beam. In addition, the deposition rate was found to exhibit a strong dependence on the total pressure in the system.