Solid-state image sensor, solid-state imaging device, and camera device
View Patent ↗The present technology relates to a solid-state image sensor, a solid-state imaging device, and a camera device capable of making white flaws unnoticeable even with a reduced cell size. The solid-state image sensor includes: a register unit formed as an n-type impurity region extending in a first direction; a reading unit configured to read charge from the photoelectric conversion unit into the register unit and formed as a p-type impurity region extending in the same direction as the register unit; a horizontal element isolation unit configured to prevent leakage of charge from the photoelectric conversion unit and formed as a p-type impurity region extending in the same direction as the register unit; and multiple transfer electrodes configured to apply voltage for changing potential distribution of the register unit, wherein a total amount of n-type impurity forming the register unit below a low-level electrode having a standby voltage of a predetermined low value among the transfer electrodes is smaller than a total amount of n-type impurity forming the register unit below a middle-level electrode having a standby voltage higher than the predetermined low value.
1. A solid-state image sensor comprising:
a register unit configured to transfer charge stored in a photoelectric conversion unit and formed as an n-type impurity region extending in a first direction;
a reading unit configured to read charge from the photoelectric conversion unit into the register unit and formed as a p-type impurity region extending in the same direction as the register unit;
a horizontal element isolation unit configured to prevent leakage of charge from the photoelectric conversion unit and formed as a p-type impurity region extending in the same direction as the register unit; and
multiple transfer electrodes configured to apply voltage for changing potential distribution of the register unit, wherein
a total amount of n-type impurity forming the register unit below a low-level electrode having a standby voltage of a predetermined low value among the transfer electrodes is smaller than a total amount of n-type impurity forming the register unit below a middle-level electrode having a standby voltage higher than the predetermined low value.
2. The solid-state image sensor according to claim 1 , wherein in the second direction perpendicular to the first direction, a width of n-type impurity forming the register unit below the low-level electrode is smaller than a width of n-type impurity forming the register unit below the middle-level electrode.
3. The solid-state image sensor according to claim 1 , wherein a concentration of n-type impurity forming the register unit below the low-level electrode is lower than a concentration of n-type impurity forming the register unit below the middle-level electrode.
4. The solid-state image sensor according to claim 1 , wherein in the second direction perpendicular to the first direction, a highest concentration position below the low-level electrode is closer to the photoelectric conversion unit than a highest concentration position below the middle-level electrode, the highest concentration positions being positions where impurity concentration of the p-type impurity region forming the reading unit or the horizontal element isolation unit is highest.
5. The solid-state image sensor according to claim 4 , wherein only for highest concentration positions in the p-type impurity region forming the reading unit among the highest concentration positions, the highest concentration position below the low-level electrode is closer to the photoelectric conversion unit than the highest concentration position below the middle-level electrode.
6. The solid-state image sensor according to claim 4 , wherein only for highest concentration positions in the p-type impurity region forming the horizontal element isolation unit among the highest concentration positions, the highest concentration position below the low-level electrode is closer to the photoelectric conversion unit than the highest concentration position below the middle-level electrode.
7. The solid-state image sensor according to claim 1 , wherein n-type impurity concentration of the sensor unit at a position corresponding to that of the low-level electrode is higher than n-type impurity concentration of the sensor unit at a position corresponding to that of the middle-level electrode.
8. The solid-state image sensor according to claim 1 , wherein p-type impurity concentration of a surface of the sensor unit at a position corresponding to that of the low-level electrode is lower than p-type impurity concentration of a surface of the sensor unit at a position corresponding to that of the middle-level electrode.
9. A solid-state imaging device comprising:
a register unit configured to transfer charge stored in a photoelectric conversion unit and formed as an n-type impurity region extending in a first direction;
a reading unit configured to read charge from the photoelectric conversion unit into the register unit and formed as a p-type impurity region extending in the same direction as the register unit;
a horizontal element isolation unit configured to prevent leakage of charge from the photoelectric conversion unit and formed as a p-type impurity region extending in the same direction as the register unit;
multiple transfer electrodes configured to apply voltage to the register unit; and
a timing generation circuit configured to supply voltage to the transfer electrodes to change potential distribution of the register unit, wherein
a total amount of n-type impurity forming the register unit below a low-level electrode having a standby voltage of a predetermined low value among the transfer electrodes is smaller than a total amount of n-type impurity forming the register unit below a middle-level electrode having a standby voltage higher than the predetermined low value.
10. A camera device comprising:
a solid state image sensor including:
a register unit configured to transfer charge stored in a photoelectric conversion unit and formed as an n-type impurity region extending in a first direction;
a reading unit configured to read charge from the photoelectric conversion unit into the register unit and formed as a p-type impurity region extending in the same direction as the register unit;
a horizontal element isolation unit configured to prevent leakage of charge from the photoelectric conversion unit and formed as a p-type impurity region extending in the same direction as the register unit; and
multiple transfer electrodes configured to apply voltage for changing potential distribution of the register unit, wherein
a total amount of n-type impurity forming the register unit below a low-level electrode having a standby voltage of a predetermined low value among the transfer electrodes is smaller than a total amount of n-type impurity forming the register unit below a middle-level electrode having a standby voltage higher than the predetermined low value;
an optical system configured to guide incident light to the solid state image sensor; and
a signal processing circuit configured to process an image signal output from a solid-state image sensor.
11. The camera device according to claim 10 , further comprising a display unit configured to display an image captured by the solid-state imaging device.
12. The camera device according to claim 10 , further comprising a recording unit configured to record data of an image captured by the solid-state imaging device.
13. A camera device according to claim 10 , further comprising an operation unit configured to generate a signal in response to an operation instruction according to a user's operation.