US Patent 7476610 Removable spacer

A method for forming semiconductor devices is provided. A gate stack is formed over a surface of a substrate. A plurality of cycles for forming polymer spacers on sides of the gate stack is provided, where each cycle comprises providing a deposition phase that deposits material on the sides of the polymer spacer and over the surface of the substrate, and providing a cleaning phase that removes polymer over the surface of the substrate and shapes a profile of the deposited material. Dopant is implanted into the substrate using the polymer spacers as a dopant mask. The polymer spacers are removed.