| 摘要 |
PURPOSE:To increase the level of a saturating signal while keeping high sensitivity and to attain high circuit integration at the same time by adding the capacitance of MIS structure newly in parallel with junction capacitance by the conventional P-N junction so as to increase the amount of a stored charge. CONSTITUTION:An insulating film 10 is formed on an N region 3 and an electrode 9 made of polysilicon is provided thereupon. When light is irradiated, a photocurrent is generated in a phototransistor (TR), and its signal charge is stored in the N region 3 being the collector of the photo TR and the source of an MOS TR. A capacitor by the MIS structure is formed newly by the insulation film 10 formed by covering at least a part of the N region 3, the electrode 9 and the N region 3, the saturated signal charge amount is increased and it is not necessary to increase the size of picture elements. For example, the insulating film 10 is made of silicon dioxide having the thickness of 500Angstrom , the electric charges to be stored in a P-N junction or over are stored and large capacitance is obtained by using a silicon nitride film. |
