In-situ sidewall passivation toward the bottom of high aspect ratio features

A semiconductor processing method comprising:

• providing a silicon-and-halogen-containing precursor and an oxygen-containing precursor to a processing region of a semiconductor processing chamber, wherein a substrate is housed within the processing region, and wherein a feature extends through one or more layers of material disposed on the substrate;
• forming plasma effluents of the silicon-and-halogen-containing precursor and the oxygen-containing precursor;
• and
• contacting the substrate with the plasma effluents of the silicon-and-halogen-containing precursor and the oxygen-containing precursor, wherein the contacting forms a silicon-oxygen-and-halogen-containing material on at least a bottom portion of the feature.

A semiconductor processing method comprising:

• providing one or more etchant precursors to a processing region of a semiconductor processing chamber, wherein a substrate is housed within the processing region, and wherein the substrate comprises one or more layers of material;
• contacting the substrate with the one or more etchant precursors, wherein the contacting etches a feature into the one or more layers of material;
• halting a flow of the one or more etchant precursors;
• providing a silicon-containing precursor and an oxygen-containing precursor to the processing region;
• forming plasma effluents of the silicon-containing precursor and the oxygen-containing precursor;
• and
• 12 contacting the substrate with the plasma effluents of the silicon-containing precursor and the oxygen-containing precursor, wherein the contacting forms a passivation material on at least a bottom portion of the feature, and wherein a temperature in the processing region is maintained at less than or about 0° C.