Infusion processing solutions for USJ and localized strained-Si using gas cluster ion beams

Infusion processing using gas cluster ion beam (GCIB) technology provides several new capabilities in the areas of ultra shallow junction formation and localized or blanket SiGe formation resulting in strained-Si. This room temperature process requires only solid phase epitaxy (SPE) anneals (<700degC) for diffusionless activation and high quality SiGe or Ge formation. Initial tests indicate all standard annealing methods are compatible with the process. For the formation of ultra shallow junctions, there are four enabling aspects to this new technology: 1) no channeling is observed, so a pre-amorphizing implant (PAI) is not required for Xj<10 nm; 2) a box-like profile of the dopant can be engineered; 3) no end of range (EOR) damage is observed when Ge is included in the cluster. This creates a self-amorphizing infusion doping step that potentially advances the use of the various diffusionless activation methods since there is no issue with junction leakage; 4) by increasing the amount of Ge incorporated in the cluster and as a result into the Si surface, the boron solid solubility (Bss) can be increased, thereby lowering the Rs and Rext for the source drain extension structures. When higher infusion doses of GeH₄ and/or SiH₄ containing clusters are used, dose controlled deposition (DCD) occurs. The DCD infusion process appears to be insensitive to surface impurities such as native oxide due to the highly localized transient thermal spike (TTS). This produces a 100% amorphous layer with no post deposition interfacial layer enabling complete single crystal epitaxial regrowth of the Ge or SiGe at temperatures down to 550degC. Since this is a room temperature process, the localized infusion and deposition are compatible with photoresist patterning