Wet and dry HF-last cleaning process for high-integrity gate oxides

The suitability of using either a wet HF process or an integrated HF vapor process prior to clustered gate stack formation is compared. When ultra pure chemicals are used for wet chemical pre-cleaning, a systematic improvement of gate oxide integrity is noticeable in case of the integrated HF vapor etching technique. This is attributed to a more effective removal of the low quality wet chemical cleaning oxide and the more controllable initiation of the oxidation process.<>