| 摘要 |
PURPOSE:To make S/N in an MOS type solid state image sensor excellent, by arranging an added capacitor comprising a thin dielectric film on a picture element electrode. CONSTITUTION:On an Si single crystal substrate 40, a source 41, a drain 42 and a gate 43 of a transistor are formed. Then, a first interlayer insulating film 45 is formed. A contact hole is provided on the source 41, and a vertical line wiring layer 44 is formed. Thereafter, a second insulating layer 46 is formed. A contact hole is provided on the drain 42, and an picture element electrode 47 is formed thereon. A light sensitive thin film is applied on the entire surface. A light sensitive layer 48 is made to remain on a flat part as much as possible. Then, a thin dielectric film 49 and a transparent electrode 50 are formed on the entire surface. The thin dielectric film increased the capacity of the picture element electrode. The thickness of the film is made as thin as possible as far as the withstanding voltage and a defect ratio permit. A material having a higher dielectric constant is desirable. A ferroelectric body can be used. For example, when PLZT of 1,500Angstrom is sputtered and the material is formed, the picture element capacity of 0.3 PF, which is close to about 100 times the conventional capacity, is obtained. The S/N can be improved by 30dB. |
