| 摘要 |
PURPOSE:To suppress a decrease in a current driving capacity in an LDD type MOSFET by completely superposing a low density source region and a high density region formed under the source region. CONSTITUTION:After a gate oxide film 2 and a gate electrode 3 are formed on a substrate 1, with the electrode 3 as a mask ions are implanted to form an N<-> type source region 61 and an N<-> type drain region 62. Then, after an SiO2 film 50 is deposited, it is anisotropically etched to allow a side wall 5 to remain only on the side of the region 51 of the gate electrode. Then, N<+> type source region 71 and N<+> type and drain region which are slightly deeper than the regions 61, 62 are formed by ion implanting. In the thus formed MOSFET, a drain breakdown voltage resistance is improved by the drain region 72, but the region 61 is almost superposed on the region 71. Thus, a current driving capacity is not decreased.
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