Improved polycrystalline silicon sheet resistance by rapid thermal annealing prior and subsequent to ion implantation

Polycrystalline Si films on oxidized Si wafers have been subjected to a rapid thermal processing anneal prior to As ion implantation. After ion implantation the films are given another rapid thermal processing anneal to activate the As. The preimplant anneal causes the as‐deposited grain size to increase by ∼ a factor of 10. These films have a 20–30% lower sheet resistance than films that were post‐implant annealed only. The increase in grain size by the preimplant anneal reduces the grain boundary area and therefore, minimizes the amount of dopant in the grain boundary relative to the grain.