Solid-state imaging apparatus and driving method thereof
AssigneeSony Corporation
InventorsRyoji Suzuki, Takahisa Ueno, Keiji Mabuchi
Life of this patent
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Abstract
Each unit pixel includes a photodiode, a reading selection transistor, a reading transistor, an amplifying transistor, a reset transistor, and a horizontal selection transistor, and thus a MOS image sensor of a dot-sequential reading 5-Tr type is formed. The reading selection transistor and the reading transistor are formed with a two-layer gate structure, and gate potential of the reading selection transistor and the reading transistor is set to a negative potential. Thereby, a lower layer of a gate region of the reading transistor and the reading selection transistor is controlled to a negative potential. Thus, depletion in the lower layer region is suppressed to reduce leakage current.
Claims19
A solid-state imaging apparatus comprising:
- a plurality of unit pixels arranged in a vertical direction and a horizontal direction in a two-dimensional matrix form;
- and, within said unit pixels,
- photoelectric converting means for accumulating a signal charge according to an amount of light received;
- a floating diffusion portion for extracting the signal charge obtained by said photoelectric converting means;
- an amplifying transistor for extracting a potential variation by the signal charge of said floating diffusion portion;
- a reading transistor for transferring the signal charge accumulated by said photoelectric converting means to the floating diffusion portion on the basis of a line selection signal;
- and
- a reading selection transistor for controlling said reading transistor on the basis of a pixel selection signal;
- wherein gate potential of at least one of said reading transistor and said reading selection transistor which is on a side of said photoelectric converting means is set to a negative potential with respect to a well region.
A driving method of a solid-state imaging apparatus, said solid-state imaging apparatus comprising:
- a plurality of unit pixels arranged in a vertical direction and a horizontal direction in a two-dimensional matrix form;
- and, within said unit pixels, photoelectric converting means for accumulating a signal charge according to an amount of light received;
- a floating diffusion portion for extracting the signal charge obtained by said photoelectric converting means;
- an amplifying transistor for extracting a potential variation by the signal charge of said floating diffusion portion;
- a reading transistor for transferring the signal charge accumulated by said photoelectric converting means to the floating diffusion portion on the basis of a line selection signal;
- and a reading selection transistor for controlling said reading transistor on the basis of a pixel selection signal;
- wherein gate electrodes of said reading transistor and said reading selection transistor are formed by using two electrode layers different from each other, gate potential of at least the transistor on a side of the photoelectric converting means is set to a negative potential, and the gate electrode of said transistor on the side of the photoelectric converting means is controlled to the negative potential in at least a part of a non-selection period.
Dependencies are inferred from the claim text.