| 摘要 |
PURPOSE:To decrease the outflow of charge from an N-type diffusion layer by a method wherein an MIS transistor is provided between the N-type diffusion layer of a transfer gate and a charge storage electrode. CONSTITUTION:N-type impurity ions are implanted into an opened contact hole 16 to form an N-type diffusion layer 14. Then, polysilicon exposed at the side wall of the contact hole 16 is thermally oxidized to form a gate oxide film 110 of an MIS transistor. At this point, a silicon substrate exposed at the base of the contact hole is oxidized. The oxide film formed on the base of the contact hole is selectively removed by anisotropic etching, and a gate oxide film is left only on the side wall of the contact. Thereafter, a polysilicon 111 containing P-type impurities low in concentration is filled into the contact hole 16. Then, a second polysilicon 17, a capacitor insulating film 18, and a third silicon 19 are successively formed through patterning. |
