Chemical oxides on Si were etched with anhydrous HF/methanol vapor phase chemistries. Passivating oxide layers were grown with varying recipes of the RCA clean. Atomic Force Microscopy (AFM) was used to characterize the vapor etched surfaces. High densities of large residue islands were observed after vapor etching of RCA chemical and SC-1 oxides. These residue islands are distributed randomly upon the Si surface. The average island height and lateral width are 6 nm and 40 nm, respectively. Smaller residue islands were observed after vapor etching oxides grown in SC-2 solutions. The average island height and lateral width are 1.3 nm and 20 nm, respectively. Surface residue was not observed as a result of vapor etching oxides grown via dilute SC-1 solutions. These results imply that the SC-1 chemical solution (H{sub}2O:NH{sub}4OH:H{sub}2O{sub}2) may be incorporating impurities in the RCA chemical oxide, which remain on the Si surface after vapor phase cleaning. Lack of an SC-1 process appears to result in minimal surface residue.
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