Imaging element with pixels having capacitors separated from substrate, drive method for imaging element, manufacturing method for imaging element, and electronic apparatus
An imaging element includes a plurality of pixels. Each of the plurality of pixels includes the following element. A photoelectric transducer is disposed in each of the plurality of pixels and is configured to generate electric charge corresponding to received light. A storage unit has a predetermined capacitance and is configured to store therein electric charge transferred from the photoelectric transducer. A capacitor is disposed separate from a silicon substrate with an interlayer insulating film therebetween, the photoelectric transducer and the storage unit being formed in the silicon substrate. A connecting unit is disposed separate from the silicon substrate with the interlayer insulating film therebetween and is configured to connect the storage unit and the capacitor.
1. An imaging element including a plurality of pixels, each of the plurality of pixels comprising:
a photoelectric transducer that generates electric charge corresponding to received light;
a storage unit that stores therein electric charge transferred from the photoelectric transducer;
a capacitor; and
a connecting transistor that selectively connects the storage unit and the capacitor,
wherein the photoelectric transducer is formed in a silicon substrate and the capacitor and the connecting transistor are formed in a wiring layer disposed separate from the silicon substrate with an interlayer insulating film therebetween.
2. The imaging element according to claim 1 , wherein the imaging element is driven such that transfer of electric charge from the photoelectric transducer to the storage unit is simultaneously performed in the plurality of pixels, and electric charge stored in the storage unit is transferred to the capacitor via the connecting transistor and is retained in the capacitor.
3. The imaging element according to claim 1 , wherein:
the capacitor is an additional capacitor configured to store electric charge therein in addition to the storing unit storing electric charge; and
the connecting transistor is driven so as to connect or disconnect the storage unit and the additional capacitor during a readout period for which a signal is read from the pixel.
4. The imaging element according to claim 3 , wherein light to be received by the photoelectric transducer is incident on a back side of the silicon substrate which opposes a side of the silicon substrate on which a wiring layer is stacked.
5. The imaging element according to claim 3 , wherein the storage unit is used for all the plurality of pixels.
6. The imaging element according to claim 3 , wherein a plurality of the capacitors are connected to the storage unit via a plurality of the associated connecting transistors.
7. The imaging element according to claim 3 , wherein a light blocking film is formed between the silicon substrate and the connecting transistor, the photoelectric transducer being formed in the silicon substrate.
8. The imaging element according to claim 1 , wherein the capacitor includes a pair of planar electrodes opposing each other and sandwiching an insulating film therebetween.
9. An electronic apparatus comprising:
the imaging element of claim 1 .
10. The electronic apparatus according to claim 9 , wherein the imaging element has a structure in which light to be received by the photoelectric transducer is incident on a back side of the silicon substrate which opposes a side of the silicon substrate on which a wiring layer is stacked.
11. The An imaging element including a plurality of pixels, each of the plurality of pixels comprising:
a photoelectric transducer that is formed in a silicon substrate and that generates electric charge corresponding to received light;
a storage unit that stores electric charge transferred from the photoelectric transducer;
a first capacitor that is disposed separate from the silicon substrate with an interlayer insulating film therebetween; and
a first connecting unit that is disposed separate from the silicon substrate with the interlayer insulating film therebetween and that selectively connects the storage unit and the first capacitor;
a second capacitor that is disposed separate from the silicon substrate with the interlayer insulating film therebetween; and
a second connecting unit that is disposed separate from the silicon substrate with the interlayer insulating film therebetween and that selectively connects the first capacitor and the second capacitor,
wherein, after a signal representing a reset level of the second capacitor is read, electric charge is transferred from the first capacitor to the second capacitor via the second connecting unit and a signal representing a level corresponding to electric charge stored in the second capacitor is read.
12. The imaging element according to claim 1 , wherein an output unit configured to output a signal representing a level corresponding to electric charge stored in the capacitor is disposed for all the plurality of pixels.
13. An imaging element including a plurality of pixels, each of the plurality of pixels comprising:
a photoelectric transducer that generates electric charge corresponding to received light;
a storage unit that stores electric charge transferred from the photoelectric transducer;
a first capacitor; and
a first connecting unit that selectively connects the storage unit and the first capacitor;
a second capacitor; and
a second connecting unit that selectively connects the storage unit and the second capacitor,
wherein the first and second capacitors and the first and second connecting units are formed in a wiring layer disposed separate from a silicon substrate with an interlayer insulating film therebetween, the photoelectric transducer being formed in the silicon substrate.
14. An electronic apparatus comprising:
the imaging element of claim 13 .
15. An imaging element including a plurality of pixels, each of the plurality of pixels comprising:
a photoelectric transducer that generates electric charge corresponding to received light;
a storage unit that stores electric charge transferred from the photoelectric transducer;
a capacitor; and
a connecting unit that selectively connects the storage unit and the first capacitor;
wherein the capacitor and the connecting unit are formed in a wiring layer disposed separate from the silicon substrate with an interlayer insulating film therebetween, the photoelectric transducer being formed in the silicon substrate, and
wherein, during a readout period for which a signal is read from the pixel, a signal is read in the state in which the storage unit and the capacitor are connected by the connecting unit and a signal is read in the state in which the storage unit and the capacitor are not connected by the connecting unit.
16. An electronic apparatus comprising:
the imaging element of claim 15 .
17. An imaging element including a plurality of pixels, each of the plurality of pixels comprising:
a photoelectric transducer that generates electric charge corresponding to received light;
a storage unit that stores electric charge transferred from the photoelectric transducer;
a capacitor; and
a connecting unit that selectively connects the storage unit and the first capacitor;
wherein the capacitor and the connecting unit are formed in a wiring layer disposed separate from the silicon substrate with an interlayer insulating film therebetween, the photoelectric transducer being formed in the silicon substrate, and
wherein the capacitor includes a pair of electrodes formed in a comb-like shape and having wiring portions, the wiring portions of one electrode and the wiring portions of the other electrode being alternately disposed with a predetermined spacing therebetween.
18. An electronic apparatus comprising:
the imaging element of claim 17 .