Plasma enhanced deposition processes for controlled formation of oxygen containing thin films

A process for selectively forming SiOC on horizontal surfaces of a three-dimensional feature on a substrate relative to vertical surfaces of the three-dimensional feature, the process comprising:

• depositing SiOC on the horizontal and vertical surfaces of the three-dimensional feature by a plasma enhanced atomic layer deposition (PEALD) process comprising at least one deposition cycle comprising:
• contacting the substrate with a silicon precursor that comprises oxygen;
• and
• contacting the substrate with a second reactant comprising plasma formed in a gas that does not comprise oxygen, wherein the SiOC deposited on at least one of the horizontal surfaces has an etch rate lower than an etch rate of the SiOC deposited on at least one of the vertical surfaces;
• and
• etching the deposited SiOC, wherein etching the deposited SiOC removes the deposited SiOC from the vertical surfaces.