Method for mixing nitrogen element in gate silicon oxide layer and process for manufacturing gate silicon oxide layer structure

The invention provides a method for mixing a nitrogen element in a gate silicon oxide layer, which comprises the following steps of: introducing N2 and O2 in a gas flow ratio of 1:3 in a main oxidation process or an annealing process for forming the gate silicon oxide layer; and forming a silicon oxynitride layer on the formed silicon oxide layer so that the nitrogen element is diffused to the gate silicon oxide layer. In the method for mixing the nitrogen element in the gate silicon oxide layer, N2O is substituted by adopting mixed atmosphere of the N2 and the O2 in a specific ratio, so that the nitrogen element can be mixed into the gate silicon oxide layer effectively in a high-temperature furnace which is not provided with an independent N2O supply system. Compared with the annealing process performed merely in inert gases, the annealing process performed under the process condition of the specific mixed atmosphere has the low heat budget value, and the quality and compactness of the ...