| 摘要 |
PURPOSE:To decrease the area occupied by active element regions and to realize an MIS-type semiconductor storage device having a large capacity, by forming grooves in a semiconductor substrate located under a plurality of transferring gates corresponding to one bit, burying the transferring gates in these grooves through an insulation film and further burying an insulating material in the grooves. CONSTITUTION:A semiconductor substrate 7 is provided with grooves 5a by means of the photoetching process, and an insulating material 4 such as SiO2 is adhered thereon so that the grooves 5a are filled with the insulating material 4. The insulating material 4 is removed by etching the same, while the material 4 in the grooves is left. Grooves 5b ar formed on the surface of the semiconductor substrate 7 in the regions where transferring gates 1 are to be formed. An insulation film 6 is formed on the surface of the semiconductor substrate 7 including the grooves 5b, and a conductive material such as polysilicon is adhered on the whole surface so that the grooves 5b are filled with the material. Subsequently, the conductive material is photoetched to form charge transferring gates 1. Similar procedures are repeated to provide transferring gates 2. An MIS semiconductor storage device is completed through further steps of forming a diffusion layer by the ion implantation, adhering an interlayer film, forming contact apertures and forming wiring layers.
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