Patent ID: 7402472
Filing Date: 2008-07-22
Classification: H01L

Abstract:
1. A method for forming a gate dielectric, comprising: forming a dielectric layer overlying a substrate; performing a first nitridation step by exposing the dielectric layer to plasma nitridation to form a plasma nitrided dielectric layer; forming an oxide layer at an interface between the substrate and the plasma nitrided dielectric layer by annealing, in the presence of oxygen, the nitrided dielectric layer to displace a portion of nitrogen from the interface thereby forming an atomically smoother interface; performing a second nitridation step by exposing the plasma nitrided dielectric layer to plasma nitridation to add more nitrogen to the plasma nitrided dielectric layer; and after the second nitridation step, annealing the plasma nitrided dielectric in the presence of oxygen layer to treat the interface between the substrate and the plasma nitrided dielectric layer by further smoothing the interface and thereby form the gate dielectric so that the interface is substantially nitrogen free; wherein the gate dielectric is formed without a deposition after the step of forming the dielectric layer.