摘要 |
In the fabrication of a MOS transistor, a single process step is performed for controlling the threshold voltage of the transistor and improving the reliability of a gate insulating film so that the number of manufacturing steps is decreased. A desired amount of fixed electric charge is provided at an interface between a semiconductor substrate and the gate insulating film by a nitriding process performed on the gate insulating film to form a channel region and control the threshold voltage of the MOS transistor, so that both an improvement in the reliability of the gate insulating film and control of the threshold voltage of the MOS transistor are performed in one step.
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