An integrated circuit includes a processor and a circuit. Wafers are exposed to a plasma for a sufficient time prior to epitaxial silicon growth, in order to clean the wafers. A process of making irradiated crosslinked polyethylene composition having reduced free radical content, preferably containing substantially no residual free radicals, by mechanically deforming the polyethylene at a temperature that is below the melting point of the polyethylene, optionally in a sensitizing environment, is also disclosed herein. The gate stack includes dielectric and polysilicon layers.