Patent ID: 8492291

Claim:
A method of manufacturing a semiconductor device, comprising: forming a gate dielectric silicon dioxide layer by thermal oxidation over a substrate; incorporating nitrogen into the silicon dioxide layer to form a nitrided silicon oxide layer having a non-uniform depth distribution of nitrogen atoms, with a nitrogen concentration profile that increases in a surface region from a surface to a maximum at about a first depth, and then decreases to a relatively uniform concentration in a bulk region extending from the first depth to a second depth at which the nitrogen concentration profile reaches a relative uniform concentration; and treating the nitrided silicon oxide layer with oxygen radicals to reduce a nitrogen concentration near the surface and reduce a non-uniformity of nitrogen in the bulk region to less than about 25%, as determined by % ⁢ ⁢ N . U . = [ N ] max - [ N ] min [ N ] avg * 100 , wherein % N.U. is the % non-uniformity of the nitrogen concentration in the bulk region, [N] max is the maximum concentration of nitrogen in the bulk region, [N] min is the minimum concentration of nitrogen in the bulk region, and [N] avg is the average concentration of nitrogen in the bulk region.