| 摘要 |
PURPOSE:To prevent the impurity of a lower-layer semiconductor film from coming up to a part being low in impurity concentration by making the concentration of the second conductive type impurity of a second semiconductor film on a second insulating film formed on the first conductive type semiconductor film on a first insulating film higher than that of the first conductive type impurity of the first semiconductor film. CONSTITUTION:A pattern 104 is formed, after silicon oxide film 102 and polysilicon film 103 are formed in a semiconductor substrate 101 and then P<+> or As<+> being N-type impurity is ion-implanted so that N-type polysilicon film is formed. Secondly, a pattern 105 is formed after the silicon oxide film is deposited, and a polysilicon film 106 is patterned after a contact is opened and the polysilicon film is formed. Subsequently, after a silicon oxide film is formed, a polysilicon film is formed, then a gate electrode 108 is formed and BF2<+> or B<+> being P-type impurity is ion-implanted with the use of the gate electrode as mask. In this case, the concentration of the P-type impurity being BF2<+> or B<+> of an upper layer is made higher than that of the P<+> or As<+> impurity of a lower layer. |
