Sin gap fill via nucleation inhibition

A method for forming a silicon nitride gap fill, comprising:

• positioning a substrate having at least one feature thereon in a process chamber, the at least one feature extending a depth from a substrate surface to a bottom surface, and having a width defined by a first sidewall and a second sidewall;
• depositing a first amorphous silicon layer on the substrate and the at least one feature;
• nitriding the first amorphous silicon layer to form a first silicon nitride layer on the substrate and the at least one feature;
• selectively oxidizing one or more portions of the first silicon nitride layer disposed on the substrate surface and on a top portion of the first and second sidewalls near an opening of the at least one feature in the substrate surface to form a silicon oxide layer on one or more portions of the substrate and inhibit silicon nucleation on the one or more oxidized portions of the first silicon nitride layer;
• selectively depositing a second silicon layer on the remaining non-oxidized portions of first silicon nitride layer on the substrate;
• and
• nitriding the second silicon layer to form a second silicon nitride layer disposed directly on the remaining non-oxidized portions of the first silicon nitride layer.

A method for forming a silicon nitride gap fill, comprising:

• positioning a substrate having at least one feature thereon in a process chamber, the at least one feature extending a depth from a substrate surface to a bottom surface, and having a width defined by a first sidewall and a second sidewall;
• performing a deposition process to deposit a first amorphous silicon layer on the substrate and the at least one feature;
• performing a plasma nitridation process on the substrate to convert the first amorphous silicon layer to a first silicon nitride layer;
• performing a plasma oxidation process to selectively oxidize one or more portions of the first silicon nitride layer on one or more portions of the substrate and at least one feature;
• performing a deposition process to selectively deposit a second amorphous silicon layer on the remaining non-oxidized portions of first silicon nitride layer on the substrate;
• performing the plasma nitridation process on the substrate to convert the second amorphous silicon layer into a second silicon nitride layer disposed directly on the remaining non-oxidized portions of the first silicon nitride layer;
• and
• repeating the selective plasma oxidation, selective deposition, and plasma nitridation processes sequentially to fill the at least one feature with silicon nitride and form the silicon nitride gap fill.