Scale-up of pulsed laser deposition (PLD) for 4″-wafer coating

PLD of uniform thin films on 4″-wafers has been realized by the integration of PLDLD-source into a commercial MBE-system. Thickness homogeneity over the total substrate area is obtained by precise spatial control of the plasma plumes excited simultaneously at two or more adjacent target locations. Computer controlled motion of a cylindrical target with respect to the stationary focal spots of the laser beams, has to provide (a) a suitable deflection of the plume axis and (b) a uniform target erosion. Process control was investigated by computer simulations. The efficiency of the two techniques for large-area coating described in this paper is illustrated by the preparation of DLC thin film specimens and their ellipsometric characterization. Special film thickness gradients were realized by a particular regime of target and substrate motion.