Effects of RCA cleaning upon breakdown voltages of thin gate oxides

Abstract

The purpose of this thesis was to investigate the effects of pre- and post-oxidation RCA cleaning on thin gate oxides through the study of breakdown voltages at several current levels. The RCA Clean consisted of SC1 (NH₄OH in H₂O₂), followed by an optional dilute HF dip, followed by SC2 (HCl in H₂O₂). SAS analysis of the experiments revealed the following results: an HF dip was not found to affect the performance of the pre-oxidation clean, SC2 was harmful to the oxide when performed after oxide growth, and the role of solution age was not clear. In addition, an interaction was found between SC1 and SC2 performed after oxide growth, with SC1 partially alleviating the harmful effects of SC2 when performed prior to SC2. This and other data led to the conclusion that SC2 was selectively etching the oxide.