Radiation detector and radiation imaging system
A radiation detector comprising: a pixel array in which pixels each having a radiation detection element configured to convert radiation into charges and an amplification transistor configured to amplify a signal from the radiation detection element and output the amplified signal are arrayed in a matrix shape; and signal wiring provided for each pixel column, wherein a pixel isolation structure formed to surround the radiation detection element in a plan view is provided, and the amplification transistor is arranged inside a region defined by the pixel isolation structure in a plan view.
1. A radiation detector comprising:
a pixel array in which pixels each having a radiation detection element configured to convert radiation into charges and an amplification transistor configured to amplify a signal from the radiation detection element and output the amplified signal are arrayed in a matrix shape; and
signal wiring provided for each pixel column,
wherein a pixel isolation structure formed to surround the radiation detection element in a plan view is provided, and
the amplification transistor is arranged inside a region defined by the pixel isolation structure in a plan view.
2. The radiation detector according to claim 1 , wherein the amplification transistor is arranged in a region surrounded by an active region of the radiation detection element.
3. The radiation detector according to claim 1 ,
wherein the pixel further has a transfer transistor configured to transfer charges converted by the radiation detection element to a charge retention unit, and
wherein the transfer transistor and the charge retention unit are also arranged inside the region defined by the pixel isolation structure in a plan view.
4. The radiation detector according to claim 1 , wherein the pixel further has wiring configured to connect an extraction unit for extracting charges from the radiation detection element and a gate of the amplification transistor.
5. The radiation detector according to claim 1 , wherein the signal wiring includes at least two signal wiring lines that are arranged with respect to a pixel column of the pixel array.
6. The radiation detector according to claim 5 ,
wherein the radiation detection element and the signal wiring lines are arranged at a same cycle as a pixel pitch in the pixel array, and
wherein the radiation detection element and the signal wiring lines are arranged to be shifted by a half phase from each other.
7. The radiation detector according to claim 5 ,
wherein the signal wiring lines are formed in a same layer as wiring that supplies a power supply voltage to the amplification transistor, and
wherein the signal wiring lines are arranged to be adjacent to each other.
8. The radiation detector according to claim 7 ,
wherein connection wiring that is provided for each amplification transistor and that is orthogonal to at least any of the signal wiring lines is provided,
wherein the signal wiring lines and the connection wiring are formed in different layers and electrically connected to each other via a via hole, and
wherein plane layouts of the pixels are substantially same in shape except for the via hole.
9. The radiation detector according to claim 8 , wherein overlapping areas of portions at which the signal wiring and the connection wiring cross each other have substantially same value at all intersecting points.
10. The radiation detector according to claim 5 ,
wherein the pixels have power supply wiring arranged parallel to the signal wiring line, and
wherein an interval between the adjacent signal wiring lines is smaller than an interval between the signal wiring line, which is adjacent to the power supply wiring, and the power supply wiring.
11. The radiation detector according to claim 10 ,
wherein the pixels include a reset transistor, and
wherein the power supply wiring includes first power supply wiring that supplies a drain potential of the amplification transistor, second power supply wiring that supplies a well potential, and third power supply wiring that supplies a drain potential of the reset transistor.
12. The radiation detector according to claim 11 , wherein the second power supply wiring is arranged between the first power supply wiring and the third power supply wiring.
13. The radiation detector according to claim 11 , wherein the third power supply wiring is arranged between the first power supply wiring and the second power supply wiring.
14. The radiation detector according to claim 11 , wherein the first power supply wiring, the second power supply wiring, and the third power supply wiring are arranged at an upper part of a region in which the amplification transistor is arranged.
15. The radiation detector according to claim 1 ,
wherein the signal wiring is arranged at an upper part of a region in which the radiation detection element is arranged, and
wherein the signal wiring includes at least three signal wiring lines per pixel column.
16. The radiation detector according to claim 1 , wherein the radiation detector is of a surface irradiation type.
17. A radiation imaging system comprising:
the radiation detector according to claim 1 ; and
a signal processing unit that processes a signal output from the radiation detector.
18. A radiation imaging system comprising:
the radiation detector according to claim 1 ; and
a radiation source.