Effect of In-Situ Native Oxide Clean on Point Defect Behavior in Si⁺ Amorphized Ion-Implanted Si

Mitigation of parasitic contact resistances require processing techniques that yield highly doped junctions such as ultra-shallow ion implantation. The depth of these junctions is so shallow that the role of the native oxide warrants further study. Investigation of an in-situ native oxide clean prior to amorphizing the surface of Si with 3×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> Si<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ions at an energy of 5 keV has been studied. HRTEM confirmed that, when the native oxide is present under these conditions, the amorphization process is incomplete, leaving near-surface crystallites embedded in the amorphous layer. However, when the oxide is removed in-situ, the samples had a continuous amorphous layer with no crystallites for the exact same implant conditions. This is the opposite of what is expected from damage simulations. Experiments with a plasma treatment and regrowth of the oxide prior to implantation show the complete amorphization process still occurs. It is proposed that hydrogen incorporation during plasma treatment may be reducing I-V recombination during the dynamic annealing stage of the implant leading to more effective amorphization. SRIM and FLOOXS simulations will be shown that support this model.