Method and system for mitigating underlayer damage during formation of patterned structures

A system comprising:

• a reaction chamber;
• a silicon precursor source;
• one or more of an oxygen reactant source and a nitrogen reactant source;
• an inert gas source;
• a flow control system;
• a plasma power source;
• an exhaust source;
• and
• a controller,
• wherein the controller is configured to control gas flow of a silicon precursor for a silicon precursor pulse, a nitrogen and/or oxygen reactant for a reactant pulse, and an inert gas for an inert gas pulse into the reaction chamber to form one or more of a silicon nitride layer and a silicon oxide layer on a surface of a substrate, wherein the controller is configured to:
• provide the silicon precursor,
• provide the nitrogen and/or oxygen reactant,
• cease providing the silicon precursor,
• after ceasing providing the silicon precursor, provide the inert gas,
• after ceasing providing the silicon precursor, providing a plasma power,
• cease providing the inert gas,
• cease providing a plasma power,
• after ceasing providing the inert gas, performing a purge,
• wherein a plasma power is pulsed during a plasma pulse period,
• wherein the nitrogen and/or oxygen reactant and the inert gas are provided to the reaction chamber for the plasma pulse period.