Surface preparation for gate oxide formation that avoids chemical oxide formation

摘要

A cleaning sequence usable in semiconductor manufacturing efficiently cleans semiconductor substrates while preventing chemical oxide formation thereon. The sequence includes the sequence of: 1) treating with an HF solution; 2) treating with pure H₂SO₄; 3) treating with an H₂O₂ solution; 4) a DI water rinse; and 5) treatment with an HCl solution. The pure H₂SO₄ solution may include an H₂SO₄ concentration of about ninety-eight percent (98%) or greater. After the HCl solution treatment, the cleaned surface may be a silicon surface that is free of a chemical oxide having a thickness of 5 angstroms or greater. The invention finds particular advantage in semiconductor devices that utilize multiple gate oxide thicknesses.