Solid source doping for source and drain extension doping

摘要

A method is provided for solid source doping for source and drain extensions. According to one embodiment, the method includes providing a substrate containing fins of first and second film stacks, sacrificial gates across and on the fins of the first and second film stacks, where the first and second film stacks include alternating first and second films, and where the first films extend through sidewall spacers on the sacrificial gates, selectively forming a first mask layer on the sidewall spacers and on the first films of the first film stack, depositing a first dopant layer on the substrate, heat-treating the substrate to diffuse dopants from the first dopant layer into the first films of the second film stack to form doped first films in the second film stack, and removing the first mask layer from the substrate. The processing steps may be repeated for the second film stack.