| 摘要 |
PROBLEM TO BE SOLVED: To provide an image sensor capable of converging an electric charge amount in an FG on a constant value. SOLUTION: An MOS image sensor has a photoelectric conversion portion PD and a pixel portion 52a having a write transistor WT. The WT includes the floating gate FG, write control gates WCG provided at positions opposed to the FG, insulating films 8 provided between the FG and WCGs, and an insulating film 7 provided between the FG and a substrate 51. The insulating film 7 has its thickness set so that electric charges are injected into the FG from the PD in a state where a first voltage is applied between the WCGs and substrate 51, and the insulating films 8 have their thickness set so that electric charges are injected into the FG from the WCGs in a state where a second voltage for generating an electric field in the opposite direction from that by the first voltage is applied between the WCGs and substrate 51, and electric charges do not tunnel the FG to the insulating films 8 in the state where the first voltage is applied between the WCGs and substrate 51. COPYRIGHT: (C)2011,JPO&INPIT
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