Methods for precleaning a substrate prior to metal silicide fabrication process

A method for removing native oxide from a substrate, comprising:

• transferring a substrate having an oxide layer disposed on a gate electrode or a source or drain regions formed in the substrate into a processing chamber;
• performing a multiple step cleaning process in the processing chamber to remove the oxide layer, wherein the multiple step cleaning process comprises:
• performing a pretreatment process on the substrate by supplying a pretreatment gas mixture into the processing chamber to form a plasma during the pretreatment process to activate the oxide layer on the substrate;
• performing an oxide removal process on the substrate by supplying a cleaning gas mixture into the processing chamber to remove the activated oxide layer from the substrate, wherein the cleaning gas mixture includes at least an ammonium gas and a nitrogen trifluoride;
• and
• performing a post treatment process on the cleaned substrate by supplying a post treatment gas mixture into the processing chamber to form a plasma during the post treatment process.

A method for removing native oxide from a substrate, comprising:

• transferring a substrate having an oxide layer disposed on a gate electrode or a source or drain regions formed in the substrate into a processing chamber;
• performing a multiple step cleaning process in the processing chamber to remove the oxide layer, wherein the multiple step cleaning process comprises:
• converting a surface of the oxide layer into a silicon hydrogen bond rich surface by a plasma generated in the processing chamber to activate the oxide layer on the substrate;
• performing an oxide removal process on the substrate by supplying a cleaning gas mixture into the processing chamber to remove the activated oxide layer from the substrate exposing the underlying gate electrode layer, wherein the cleaning gas mixture includes at least an ammonium gas and a nitrogen trifluoride;
• and
• converting the exposed gate electrode into a silicon hydrogen bond rich surface by a plasma generated in the processing chamber.