| 摘要 |
PURPOSE: To prevent undesired voltage shift by an arrangement wherein an overlying layer serves to shield a laminated gate and a part of underlying substrate and then source and drain regions are formed by exposing the substrate to dopant species. CONSTITUTION: A laminated gate 17 including a gate oxide 13 and a doped silicon conductor is provided on a substrate 11. A thick thermal oxide layer 27 is then formed on the doped silicon conductor 15 by oxidation process from above the silicon surfaces 21, 23. The layer 27 may be as thick as about 120Åabove the conductor 15 and about 55Åabove the silicon regions 21, 23. More specifically, a relatively tick protective film 35 is formed on the polysilicon gate 15 and thin protective film 33, 31 are formed on the silicon surfaces 21, 23. After a gate 17 is protected by an oxide layer 35, the dopant species are directed toward the substrate 11.
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