| 摘要 |
PURPOSE:To prevent generation interface barrier and obtain good contact by suppressing generation of natural oxide through existence of N<+> type layer when providing an ohmic contact between polycrystalline Si and substrate Si. CONSTITUTION:A thick field oxide film 22 is formed to the periphery of P-type Si substrate 21, a thin first gate oxide film 23 which becomes a capacitor is deposited between such field oxide films and an N-type first gate electrode 24 is provided thereon. Next, this electrode 24 is oxidized, an inter-layer insulation film 25 is generated only at the surfacelayer, it is covered with the second gate oxide film 26 and an N-type second gate electrode 27 is formed thereon. Thereafter, the substrate 21 is exposed removing the film 26 other than that under the electrode 26, a couple of N<-> type regions 28 are provided per cell, and these are used as the source and drain of transfer transistor. Thereafter, the entire part is covered wihan oxide film 32, an aperture 34 is formed, and the N<+> type region 35 is generated in the source region by diffusing N-type impurity and in addition polycrystalline Si wiring layer 33 is formed thereon. |
