Role of UV/chlorine exposure during dry surface conditioning before integrated epi deposition process
Ruzyllo, J × Rohr, E Caymax, M Baeyens, M Conard, T Mertens, P Heyns, Marc #
Diffusion and Defect Data B, Solid State Phenomena vol:65-6 pages:233-236
Native/chemical oxide etching using the anhydrous HF (AHF)/methanol process before epitaxial deposition was investigated in a cluster incorporating surface processing module and epi deposition reactor. The results of this research indicate that the AHF/methanol process alone leaves the Si surface in a state which does not allow growth of the haze-free epitaxial layer at 800 degrees C. If the surface is exposed to chlorine ambient following oxide etch, however, haze is eliminated and a high quality epi layer is grown. This effect is attributed primarily to the reduction of fluorine remaining on the surface following AHF/methanol oxide etch by chlorine. The proposed pre-epi surface preparation procedure, which does not involve any elevated temperature step, shows excellent promise for low-temperature fully integrated epitaxial processes.