| 摘要 |
PURPOSE: A method for controlling a threshold voltage in a semiconductor device is provided to be capable of restraining damage in ion-implantation for controlling the threshold voltage. CONSTITUTION: A pad oxide layer(12), a buffer polysilicon layer(13) and a nitride layer(14) are sequentially formed on a semiconductor substrate(11) having twin wells. Impurity ions for controlling a threshold voltage are implanted into the entire surface of the resultant structure. After forming a photoresist pattern(15) so as to expose a P-channel region, impurity ions for controlling P-channel threshold voltage are implanted into the exposed P-channel region. After removing the photoresist pattern(15), a field oxide layer(16) is then formed.
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