Patent ID: 7109098

Claim:
A method of forming semiconductor junctions in a semiconductor material of a workpiece, comprising: ion implanting dopant impurities in selected regions of said semiconductor material; introducing an optical absorber material precursor gas into a chamber containing the workpiece; generating an RF oscillating toroidal plasma current in a reentrant path that includes a process zone overlying said workpiece by applying RF source power, so as to deposit a layer of an optical absorber material on said workpiece; optically annealing said workpiece so as to activate dopant impurities in said semiconductor material; applying bias power or voltage to the workpiece; wherein said optical absorber material comprises amorphous carbon and said precursor gas comprises a carbon-containing gas; including an absorption-enhancing species in the optical absorbing layer by adding an optical absorption enhancing species precursor gas to the optical absorber material precursor gas during deposition of the optical absorber material; and changing the proportion of the optical absorption-enhancing precursor gas in the chamber over time to vary the absorption characteristic over the depth of the optical absorber layer.