| 摘要 |
PURPOSE:To increase the occupation area of a capacitor by a method wherein the gate electrode and the capacitor electrode of a transistor are formed of the same material and in the same process without being extended on the element isolation region, in a dynamic memory device wherein a memory cell of 1 bit is composed of a piece of MOS transistor and MOS capacitor, respectively. CONSTITUTION:The first thin gate oxide film 22 and the second much thinner gate oxide film 23 are connected and adhered on a P type Si substrate 21, and an N type polycrystalline Si film 24 is deposited over the entire surface. Next, the mask of a resist film 25 having an aperture at the element forming region is provided and etched, thus boring a groove going into the substrate, which groove is filled with an SiO2 film 26. Thereafter the resist film 25 is renewed to a resist film 27 covering the gate electrode 32 and the capacitor 33 and etched, thus removing the exposed unnecessary polycrystalline Si film 24. Then, the N<+> source and drain regions 28 serving as a bit line are diffusion-formed on the exposed surfaces of the substrate 21 outside the film 26 and the electrode 32 and between the electrode 32 and 33. |
