Real time measurement of deposition initiation and rate in laser chemical vapor deposition

Abstract

Laser chemical vapor deposition (LCVD) is a modification of conventional CVD using a laser heat source. Although the reactant systems used may be similar to conventional CVD, the film growth characteristics may differ in several ways. The changes in the optical properties of the film/substrate during deposition must be considered as the amount of laser energy absorbed determines the surface temperature and the maximum deposition rate. Also affecting the deposition rate is the diffusion of reactants to the reaction zone. Because of the small area heated in LCVD, higher surface temperatures can be accessed before diffusion and convection limit the deposition rate. For favorable reactant systems, very rapid deposition rates (greater than 100 μm/sec) and scan speeds for line deposition (greater than 10 cm/sec) can be achieved.