SOLID-STATE IMAGING DEVICE AND METHOD FOR DRIVING THE SAME

• US 20110164162A1
• Filed: 03/15/2011
• Published: 07/07/2011
• Est. Priority Date: 09/25/2008
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: KATO, Yoshiaki
• Application Number:
  US13/048,128
• Publication Number:
  US 20110164162A1
• Time in Patent Office: Days
• US Class Current: 348/311
• CPC Class Codes: H04N 25/672 between adjacent sensors or output registers for reading a single image
• CPC Class Codes: H04N 25/713 Transfer or readout registers; Split readout registers or multiple readout registers

Abstract

A solid-state imaging device includes vertical transfer units each of which is configured to transfer charge read from light receiving units, a first horizontal transfer unit and a second horizontal transfer unit each of which includes a plurality of transfer gate electrodes arranged in parallel to one another, a sorting transfer unit configured to transfer charge between the horizontal transfer units, and an output unit. In the first horizontal transfer unit, the transfer gate electrodes extend from the vertical transfer units toward the sorting transfer unit, and at least a part of each of the plurality of transfer gate electrodes located closer to the vertical transfer units is obliquely extends so that a horizontal distance from the output unit increases as it extends toward the sorting transfer unit.

Claims

1. A solid-state imaging device, comprising:

a plurality of light receiving units arranged in a two-dimensional array;

a plurality of vertical transfer units each of which is configured to transfer charge read from an associated one of the plurality of the light receiving units in a vertical direction;

a plurality of horizontal transfer units each of which is configured to transfer the charge transferred by the vertical transfer units in a horizontal direction and includes a plurality of transfer gate electrodes arranged in parallel to one another on a substrate, the plurality of horizontal transfer units being arranged in the vertical direction;

a sorting transfer unit which includes at least one shift gate electrode being provided on the substrate and extending in the horizontal direction, is provided between the plurality of the horizontal transfer units, and is configured to transfer charge between the plurality of the horizontal transfer units; and

an output unit configured to detect the charge transferred by the plurality of horizontal transfer units,

wherein

in a first horizontal transfer unit which is one of the plurality of the horizontal transfer units other than one of the horizontal transfer units located farthest from the vertical transfer units, the plurality of transfer gate electrodes extend from a side of the first horizontal transfer unit located closer to the vertical transfer units toward the sorting transfer unit located adjacent to the first horizontal transfer unit in the vertical direction, and at least a part of each of the plurality of transfer gate electrodes located closer to the vertical transfer units obliquely extends so that a horizontal distance from the output unit increases as it extends toward the sorting transfer unit located adjacent to the first horizontal transfer unit in the vertical direction.

2. The device of claim 1, wherein

the first horizontal transfer unit is one of the plurality of horizontal transfer units located closest to the vertical transfer unit.

3. The device of claim 1, wherein

in the first horizontal transfer unit, an entire part of each of the plurality of transfer gate electrodes obliquely extends so that the horizontal distance from the output unit increases as it extends toward the sorting transfer unit.

4. The device of claim 1, wherein

in the first horizontal transfer unit, potential packet regions are respectively formed immediately under parts of the plurality of transfer gate electrodes facing the sorting transfer unit located adjacent to the first horizontal transfer unit in the vertical direction, and each of the potential packet regions has a lower potential than potentials of regions located immediately under other parts of the transfer gate electrodes.

5. The device of claim 4, wherein

a concentration of an n-type impurity contained in each of parts of the substrate respectively located in the potential packet regions is higher than a concentration of an n-type impurity contained in each of parts of the substrate which are respectively located immediately under the plurality of transfer gate electrodes and are other than the potential packet regions.

6. The device of claim 4, wherein

a storage region configured to store charge and a barrier region whose potential is higher than a potential of the storage portion are formed immediately under each of the plurality of transfer gate electrodes, and comparing the regions provided immediately under the transfer gate electrode, a width of the storage region is wider in the potential packet region than those in the other regions under the transfer gate electrode.

7. The device of claim 1, wherein

in the first horizontal transfer unit, each of the plurality of transfer gate electrodes includes a bent portion which is bent so that an end portion of the transfer gate electrode located closer to the sorting transfer unit located adjacent to the first horizontal transfer unit in the vertical direction extends in the vertical direction.

8. The device of claim 1, wherein

in the first horizontal transfer unit, each of the plurality of transfer gate electrodes includes a portion which makes an acute angle with the vertical direction, when viewed in a plan view, and obliquely extends toward the sorting transfer unit located adjacent to the first horizontal transfer unit in the vertical direction.

9. The device of claim 1, wherein

a shape and an arrangement of the plurality of transfer gate electrodes in each of the plurality of the horizontal transfer units are substantially the same as those of the plurality of transfer gate electrodes in the first horizontal transfer units.

10. A method for driving a solid-state imaging device, the solid-state imaging device including a plurality of light receiving units arranged in a two-dimensional array, a plurality of vertical transfer units, a plurality of horizontal transfer units each of which includes a plurality of transfer gate electrodes arranged in parallel to one another on a substrate, the plurality of horizontal transfer units being arranged in the vertical direction, a sorting transfer unit which includes at least one shift gate electrode being provided on the substrate and extending in the horizontal direction, and is provided between the plurality of the horizontal transfer units, and an output unit provided for each of the plurality of the horizontal transfer units, the solid-state imaging device being configured so that in a first horizontal transfer unit which is one of the plurality of the horizontal transfer units located closest to the vertical transfer unit, the plurality of transfer gate electrodes extend from the vertical transfer units toward the sorting transfer unit located adjacent to the first horizontal transfer unit, and at least a part of each of the plurality of transfer gate electrodes located closer to the vertical transfer units obliquely extends so that a horizontal distance from the output unit increases as it extends toward the sorting transfer unit, the method comprising the steps of:

(a) transferring charge read from the plurality of light receiving units in the vertical direction toward the first horizontal transfer unit by the vertical transfer units;

(b) moving the charge transferred in the step (a) in the horizontal direction and moving the charge in the vertical direction;

(c) applying a control voltage to the at least one shift gate electrode to sort a part of the charge transferred in the step (a) and transferring the sorted part from the first horizontal transfer unit to a second transfer unit which is one of the plurality of horizontal transfer units located adjacent to the first horizontal transfer unit via the sorting transfer unit; and

(d) transferring, after the steps (b) and (c), charge in the first horizontal transfer unit and the second horizontal transfer unit in the horizontal direction toward the output unit.

11. The method of claim 10, wherein

in the first horizontal transfer unit, potential packet regions are respectively formed immediately under parts of the plurality of transfer gate electrodes facing the sorting transfer unit, and each of the potential packet regions has a lower potential than potentials of regions located immediately under other parts of the transfer gate electrodes, and

in the step (b), charge is stored in the potential packet regions.

12. The method of claim 10, further comprising the step of:

(e) applying a control voltage to the at least one shift gate electrode to sort a part of the charge transferred in the step (a) and transferring the sorted part from the first horizontal transfer unit to the second transfer unit via the sorting transfer unit, after the step (a) and before the step (b).

13. The method of claim 12, wherein

the step (b) and the step (c) are repeated as a set several times.

14. The method of claim 10, further comprising the step of:

(f) transferring charge in the first horizontal transfer unit and the second horizontal transfer unit in the reverse horizontal direction toward the output unit.