| 摘要 |
The present invention relates to a method of manufacturing a non-volatile semiconductor device, having a floating gate overlying a tunnel insulating film set on a silicon substrate and a control gate overlying an inter-gate insulating film set on said floating gate; which comprises the steps of: forming a silicon oxide film on the surface of the silicon substrate and subsequently applying a heat treatment thereto in atmosphere of a nitriding gas containing nitrogen oxide so as to form a nitridation region and thereby forming a tunnel insulating film; wherein in said heat treatment performed in atmosphere of the nitriding gas, so that the maximum nitrogen atomic concentration in the tunnel insulating film that is to be formed may become equal to or greater than the maximum nitrogen atomic concentration(acceptable maximum nitrogen atomic concentration) capable to provide given acceptable holding characteristics, the pressure of said nitriding gas and the temperature of heat treatment are controlled on the basis of a pre-formed relationship equation between the thickness of the tunnel insulating film and the acceptable maximum nitrogen atomic concentration, for a prescribed thickness of the tunnel insulating film that is to be formed.
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