| 摘要 |
PURPOSE:To reduce the parasitic capacity of the MOS semiconductor device by setting each value at C1>C2>C3, where the impurity density under the insulating film of the first gate is represented by C1, the impurity density under the insulating film of the second gate is represented by C2 and the impurity density of a substrate is represented by C3. CONSTITUTION:Boron ions are implanted to a p type Si substrate 1 having for example 5X10<14>/cm<3> of impurity density, and the first gage 6 is thus formed. Subsequently, phosphorus is diffused, and n<+> type regions 3, 4 are formed for contact. A photoresist mask 8 is then formed, boron ions are again implanted, and the first and second gates 6, 9 are formed. Thus, the impurity density of the p<+> type first gate 6 side becomes 1X10<16>/cm<3> and the impurity density of p<+> type second gate 9 side becomes 5X10<15>/cm<3>. Thereafter, molybdenum is formed by spattering, and the first and second gate electrodes G1, G2 are formed. |
