Method for manufacturing a thin gate dielectric layer for integrated circuit fabrication

Abstract

The present disclosure provides a method for forming a gate stack structure for semiconductor devices. The disclosed method comprises steps such as forming a dielectric layer on a substrate; applying a plasma nitridation process on the formed dielectric layer; applying a first anneal process on the deposited dielectric layer; etching the dielectric layer to a predetermined thickness using a diluted etchant; applying a second anneal process using an oxygen environment on the etched dielectric layer after the etching; and forming a gate electrode layer on top of the dielectric layer. The etching makes the top portion of the etched dielectric layer have a significantly higher concentration of nitrogen than the lower portion of the etched dielectric layer so as the leakage current is significantly reduced.