Optimization of Resist Ash Processes on Si0.45Ge0.55 Substrates for Post Extension-Halo Ion Implantation

Abstract

State-of-the-art and conventional post extension-halo resist ash and clean sequences for SixGe1-x channels have been studied. The main goal of this work was to assess the effect of post ion implant ash plasma chemistry exposure on Si0.45Ge0.55 substrate oxidation and loss. Ashing photoresist with widely used oxidizing and F- containing plasma's, result in the formation of thermally unstable and chemical reactive GeO2. By reducing the oxygen flow or applying "controlled oxygen diffusion" plasma's (COD's) one can suppress Si0.45Ge0.55 substrate oxidation, resulting in better dopant retention and as a consequence improved junction performance in real devices.