Conformal damage-free encapsulation of chalcogenide materials

A method for processing a substrate, the method comprising:

• providing a substrate comprising one or more exposed layers of chalcogenide material in a plasma chamber;
• forming an encapsulation bilayer comprising a first silicon nitride layer having a first film density and a second silicon nitride layer having a second film density over the chalcogenide material by:
• depositing the first silicon nitride layer having the first film density directly on the one or more exposed layers of the chalcogenide material by exposing the one or more layers of chalcogenide material to a pulsed plasma plasma-enhanced chemical vapor deposition process in the plasma chamber;
• and
• depositing the second silicon nitride layer having the second film density over the first silicon nitride layer having the first density by atomic layer deposition in the plasma chamber, wherein depositing the first silicon nitride layer by pulsed plasma plasma-enhanced chemical vapor deposition and depositing the second silicon nitride layer by atomic layer deposition occur without breaking vacuum,
• wherein the first film density is less than the second film density, and
• wherein the first silicon nitride layer is located between the one or more exposed layers of chalcogenide material and the second silicon nitride layer.