VNAND tensile thick TEOS oxide

A method for processing a substrate, comprising:

• positioning a substrate having a gate stack deposited thereon, the gate stack comprising a plurality of first layers and a plurality of second layers disposed alternatingly in a vertical arrangement perpendicular to a top surface of the substrate;
• forming a first oxide layer on exposed surfaces of the gate stack using a first RF power and a first process gas comprising a TEOS gas and a first oxygen-containing gas;
• after the first oxide layer has reached a predetermined thickness, ramping up the first RF power while continuing the flow of the TEOS gas and the first oxygen-containing gas to form an initiation layer of oxide over the first oxide layer;
• after the initiation layer has reached a predetermined thickness, increasing the RF power used to form the initiation layer and turning off the flow of the TEOS gas to form a transition layer of oxide on the initiation layer;
• and
• forming a second oxide layer over the transition layer using a second RF power that is different from the first RF power and a second process gas comprising a silane gas and a second oxygen-containing gas.