Gas-phase surface processing prior to 3.2 nm gate oxidation
Ruzyllo, J × Rohr, E Baeyens, M Bearda, T Mertens, P Heyns, Marc #
Diffusion and Defect Data B, Solid State Phenomena vol:65-6 pages:85-88
The pre-gate oxidation processing of Si surfaces involving an SCI clean followed by a sequence of gas-phase low pressure exposures to AHF/methanol, UV/Cl-2, and UV/O-2 is investigated. A comparison with a wet clean shows inferior performance of the dry chemistries in terms of Ca removal and surface roughness (Rms= 0.07 nm and 0.31 respectively). In spite of these apparent deficiencies the 3.2 nm thick gate oxides grown on dry cleaned surfaces are displaying electrical characteristics, particularly charge-to-breakdown, comparable to oxides grown on the wet cleaned surfaces. The possible reasons for this effect are considered.