A method of forming semiconductor junctions in a semiconductor material of a workpiece includes ion implanting dopant impurities in selected regions of the 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 the workpiece by applying RF source power, so as to deposit a layer of an optical absorber material on the workpiece, and optically annealing the workpiece so as to activate dopant impurities in the semiconductor material.