JP2016111432A - Radiation detection apparatus and radiation detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for improving accuracy of irradiation information of a radiant ray to be acquired in a radiation detection apparatus.SOLUTION: In a radiation detection apparatus, a photographing area includes first pixels for acquiring an image and second pixels for acquiring irradiation information of a radiant ray, the first pixel has a first conversion element including a first electrode arranged on a substrate and a second electrode arranged on the first electrode, and the second pixel has a conversion circuit including a second conversion element arranged on the substrate to generate a signal based on a radiant ray applied to the second pixel. The radiation detection apparatus further includes a bias line for connecting a bias power supply for driving the first conversion element to the second electrode and a detection line for transmitting the signal generated by the second conversion element to a detection circuit existing on the outside of the photographing areas, and the detection line is arranged across the second electrode through the first electrode.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radiation detection apparatus and a radiation detection system.

  Radiation detectors that detect radiation in a two-dimensional array are widely used. In recent years, multi-functionalization of such a radiation detection apparatus has been studied, and as one of them, the incorporation of an automatic exposure control (AEC) function has been studied. The AEC function is used as a means for the radiation detection apparatus to acquire irradiation information while the radiation source is irradiating radiation. For example, it can be used for acquisition of irradiation start timing at which radiation is irradiated from a radiation source, acquisition of irradiation stop timing at which radiation irradiation is stopped, acquisition of instantaneous radiation dose or integrated dose of radiation, and the like. Further, for example, when the integrated irradiation amount is monitored, and the integrated irradiation amount reaches an appropriate amount, the radiation detection device can control the radiation source to end the radiation irradiation.

  Patent Document 1 discloses a radiation detection apparatus in which pixels for image acquisition and detection pixels for irradiation information acquisition are provided in a matrix in a detection region for detecting radiation. The irradiation information signal based on the radiation irradiation acquired by the detection pixel is read out by a readout circuit provided outside the pixel region via a wiring (detection wiring) arranged in the matrix. Thereby, the radiation detection apparatus acquires radiation irradiation information.

JP 2012-15913 A

  In the structure of Patent Document 1, there are a large number of opposing portions between the individual electrode for reading out the charge of the image acquisition pixel and the detection wiring. For this reason, the present inventor has found that the parasitic capacitance between the detection wiring and the individual electrode cannot be ignored. In the radiation detection apparatus having such a structure, when reading the irradiation information signal acquired by the detection pixel during the radiation irradiation, the potential fluctuation of the individual electrode of the pixel caused by the radiation irradiation is transmitted to the detection wiring through the parasitic capacitance. As a result, crosstalk in which the potential of the detection wiring fluctuates occurs. Due to the crosstalk through the parasitic capacitance, it is difficult to accurately obtain irradiation information during radiation irradiation. An object of this invention is to provide the technique which improves the accuracy of the irradiation information of the radiation to acquire in a radiation detection apparatus.

  In view of the above problems, one aspect of the present invention provides an imaging region having a first pixel for acquiring an image in which radiation is detected and a second pixel for acquiring radiation irradiation information. A first pixel includes a first electrode disposed on a substrate and a second electrode disposed on the first electrode. The radiation detection apparatus includes: a first electrode disposed on the substrate; The second pixel has a conversion circuit including a second conversion element disposed on the substrate and generates a signal based on the radiation irradiated to the second pixel, and the radiation detection is performed. The device generates an insulating layer covering the first conversion element and the conversion circuit, a bias line for connecting the second electrode to a bias power source for driving the first conversion element, and a second conversion element A detection line for transmitting the processed signal to a detection circuit outside the imaging region, and the detection line The first electrode to the second electrode, characterized in that arranged on the opposite side.

  The above means provides a technique for improving the accuracy of the acquired radiation irradiation information in the radiation detection apparatus.

1 is an overall view of a radiation detection apparatus according to a first embodiment of the present invention. FIG. 2 is an equivalent circuit diagram of a pixel and a readout circuit of the radiation detection apparatus of FIG. 1. The top view of the detection pixel periphery of the radiation detection apparatus of FIG. Sectional drawing of the pixel of the radiation detection apparatus of FIG. The figure which shows the modification of sectional drawing of the pixel of the radiation detection apparatus of FIG. The figure which shows the modification of the top view of the detection pixel periphery of the radiation detection apparatus of FIG. The figure which shows another modification of sectional drawing of the pixel of the radiation detection apparatus of FIG. The figure which shows the modification of the whole figure of the radiation detection apparatus of FIG. 1, and the equivalent circuit schematic of a pixel. The figure which shows another modification of the top view of the detection pixel periphery of the radiation detection apparatus of FIG. The equivalent circuit diagram of the pixel and readout circuit of the radiation detection apparatus which concern on the 2nd Embodiment of this invention. The top view of the detection pixel periphery of the radiation detection apparatus of FIG. FIG. 11 is a cross-sectional view of a pixel of the radiation detection apparatus in FIG. 10. FIG. 3 is a layout view of the radiation detection apparatus according to the embodiment of the present invention with respect to the radiation source. The figure which shows the example of arrangement | positioning of the detection pixel of the radiation detection apparatus which concerns on embodiment of this invention, and the figure which shows the example of a drive timing of a detection pixel. FIG. 15 is an equivalent circuit diagram around the detection pixel in FIG. 14. The figure explaining the structural example of the radiation detection system using the radiation detection apparatus which concerns on embodiment of this invention.

  Hereinafter, specific embodiments of a radiation detection apparatus according to the present invention will be described with reference to the accompanying drawings. Note that, in the following description and drawings, common reference numerals are given to common configurations over a plurality of drawings. Therefore, a common configuration is described with reference to a plurality of drawings, and a description of a configuration with a common reference numeral is omitted as appropriate.

First Embodiment With reference to FIGS. 1 to 9, the structure of a radiation detection apparatus according to a first embodiment will be described. FIG. 1 is an overall view schematically showing a radiation detection apparatus 101 according to the first embodiment. A plurality of pixels are arranged in an array in a two-dimensional matrix in the imaging region 107 for detecting radiation of the radiation detection apparatus 101. The plurality of pixels arranged in the imaging region 107 includes two types of pixels. One is an imaging pixel 110 that is a first pixel for acquiring an image in which radiation is detected, and the other is a detection pixel 111 that is a second pixel for acquiring radiation irradiation information. In the present embodiment, only two types of pixels are arranged in the imaging region 107, but other types of pixels may be arranged. Although only one detection pixel 111 is shown in FIG. 1 for ease of explanation, a plurality of detection pixels 111 may be scattered in the imaging region 107. A plurality of detection pixels 111 may be connected in the row or column direction, or may be arranged so as to be biased toward a specific region.

  Each imaging pixel 110 is connected to a control line 150, a signal line 160, and a bias line 190. The control line 150 is arranged in the row direction and connects the imaging pixel 110 and the scanning circuit 102. The signal line 160 is arranged in the column direction and connects the imaging pixel 110 and the readout circuit 103. The bias line 190 is connected to the bias power source 105 and supplies a bias potential for the conversion element of the imaging pixel 110 to convert radiation into electric charge. In the radiation detection apparatus 101, by driving the scanning circuit 102, the output signal of the imaging pixel 110 is read out by the reading circuit 103 via the signal line 160. As a result, a two-dimensional image used for diagnosis is obtained.

  The detection pixel 111 is connected to the detection pixel control line 108, the detection line 161, and the bias line 190. The detection pixel control line 108 connects the detection pixel 111 and the detection pixel scanning circuit 106. The detection line 161 connects the detection pixel 111 and the detection pixel readout circuit 104 which is a detection circuit arranged outside the imaging region 107. The bias line 190 is connected to the bias power source 105 and supplies a bias potential for driving the conversion element of the detection pixel 111. By driving the detection pixel scanning circuit 106, an irradiation information signal generated based on the radiation applied to the detection pixel 111 is read out by the detection pixel reading circuit 104 via the detection line 161. With this output signal from the detection pixel 111, irradiation information such as irradiation start and irradiation stop timing, instantaneous irradiation amount, integrated irradiation amount, etc., reaching the place where the detection pixel 111 is arranged can be obtained.

  The detection line 161 may be arranged so as to cross over the imaging pixel 110. In the radiation detection apparatus 101 illustrated in FIG. 1, among the imaging pixels 110, a pixel that the detection line 161 crosses over the pixel is represented as a detection line passing pixel 112.

  In the present embodiment, the scanning circuit 102, the reading circuit 103, the bias power source 105, and the detection pixel scanning circuit 106 are arranged outside the imaging region 107. In the present embodiment, the readout circuit 103 and the detection pixel readout circuit 104 are provided as independent readout circuits. However, the readout circuit 103 and the detection pixel readout circuit 104 may be an integrated readout circuit. Good.

  2A and 2B show equivalent circuits of the imaging pixel 110 and the detection pixel 111. FIG. The imaging pixel 110 includes a photoelectric conversion element 120 that is a first conversion element and a switch element 130 that is a first switch element. The photoelectric conversion element 120 includes a first electrode 125, a second electrode 126, and a conversion unit 124. For example, a transistor is used as the switch element 130. The switch element 130 includes a drain electrode 135, a source electrode 136, and a gate electrode 132. The first electrode 125 is connected to the drain electrode 135. The first electrode 125 is an individual electrode that reads a signal from each of the photoelectric conversion elements 120 of each pixel, and an output signal of each pixel from the first electrode 125 to the reading circuit 103 via the switch element 130 and the signal line 160. Will be sent. The second electrode 126 is connected to the bias line 190. The second electrode 126 is a common electrode for each photoelectric conversion element of each pixel, and a bias potential is supplied from the bias power source 105. The source electrodes 136 of the switch elements 130 of the imaging pixels 110 arranged in the column direction are connected to a common signal line 160 in the column direction. The gate electrodes 132 of the switch elements 130 of the imaging pixels 110 arranged in the row direction are connected to a common control line 150 in the row direction. The ON / OFF of the switch element 130 is controlled by the potential applied to the gate electrode 132. The equivalent circuit of the detection line passing pixel 112 may be the same as the equivalent circuit of the imaging pixel 110.

  The detection pixel 111 includes a conversion circuit including a photoelectric conversion element 121 that is a second conversion element, and a switch element 131 that is a second switch element. In the present embodiment, the conversion circuit includes a photoelectric conversion element and a second switch element. The conversion circuit may include an amplifier circuit, for example. The photoelectric conversion element 121 includes a third electrode 1251, a fourth electrode 1261, and a conversion unit 1241. For example, a transistor is used as the switch element 131. The switch element 131 includes a drain electrode 1351, a source electrode 1361, and a gate electrode 1321. The third electrode 1251 is connected to the drain electrode 1351. An output signal based on the radiation applied to the photoelectric conversion element 121 of the detection pixel 111 is transmitted from the third electrode 1251 to the detection pixel readout circuit 104 via the switch element 131 and the detection line 161. The fourth electrode 1261 is connected to the bias line 190. The fourth electrode 1261 is supplied with a bias potential from the bias power source 105, similarly to the second electrode 126 of the imaging pixel 110 and the detection line passing pixel 112. The source electrode 1361 of the switch element 131 of the detection pixel 111 arranged in the column direction is connected to the detection line 161. The gate electrode 1321 of the switch element 131 of the detection pixel 111 arranged in the row direction is connected to the detection pixel control line 108. The ON / OFF of the switch element 131 is controlled by the potential applied to the gate electrode 1321.

  Next, the bias power supply 105, the readout circuit 103, and the detection pixel readout circuit 104 will be described. In order to cause the photoelectric conversion element 120 of the imaging pixel 110 to perform a photoelectric conversion operation, a voltage applied between the first electrode 125 and the second electrode 126 of the photoelectric conversion element 120, that is, between the bias power supply 105 and the readout circuit 103. Set the potential difference between them appropriately. Specifically, this potential difference is set so that a depletion layer is formed in at least a part of a semiconductor layer such as a PIN photodiode or a MIS type element that constitutes the conversion unit 124 of the photoelectric conversion element 120. Similarly, in order to cause the photoelectric conversion element 121 of the detection pixel 111 to perform a photoelectric conversion operation, a voltage applied between the third electrode 1251 and the fourth electrode 1261, that is, the bias power supply 105 and the detection pixel readout circuit 104, The potential difference between is set appropriately. Under these conditions, the reference potential of the readout circuit 103, the reference potential of the detection pixel readout circuit 104, and the potential of the bias power source 105 when operating the radiation detection apparatus 101 may be freely selected. Further, the signal readout method in the readout circuit 103 and the detection pixel readout circuit 104 may be any method such as a charge readout method, a voltage readout method, and a current readout method. FIG. 2C shows an example of an equivalent circuit of a charge readout method that can be used as the readout circuit 103 and FIG. 2D as the detection pixel readout circuit 104. The reference potential of the readout circuit 103 and the detection pixel readout circuit 104 is the reference potential of each integrating amplifier, and is, for example, the ground potential (GND potential) in the case of FIGS. 2 (c) and 2 (d). In this case, the voltages applied to the photoelectric conversion element 120 and the photoelectric conversion element 121 are both equal to the potential difference between the bias power supply 105 and the GND potential.

  FIG. 3 shows a plan view around the detection pixel 111. FIG. 3 shows two imaging pixels 110, one detection pixel 111, and one detection line passing pixel 112 in the imaging region 107. The size of one side of the photoelectric conversion element 120 and the photoelectric conversion element 121 is, for example, about 100 to 200 μm, and the interval between the adjacent photoelectric conversion elements 120 and the distance between the adjacent photoelectric conversion elements 120 and the photoelectric conversion elements 121. The interval is, for example, about 5 to 20 μm.

  FIG. 4 shows a cross-sectional view of the imaging pixel 110, the detection pixel 111, and the detection line passage pixel 112. 4A to 4C are cross-sectional views of each pixel from A-A ′ to C-C ′ in FIG. 3. Each pixel is formed on the substrate 100 in the imaging region 107. In this embodiment, an insulating substrate is used as the substrate 100, and inverted staggered amorphous silicon thin film transistors (TFTs) are used as the switch elements 130 and 131. Further, PIN photodiodes are used as the conversion units 124 and 1241. However, the present invention is not limited to this. As the substrate 100, for example, an insulating substrate such as glass or plastic may be used. For example, a semiconductor substrate using silicon or a conductor substrate using metal such as aluminum may be used as the substrate 100. When a semiconductor substrate or a conductor substrate is used as the substrate 100, a part or the entire surface of the substrate 100 may be covered with an insulating film. Further, for example, a top gate type TFT may be used for the switch elements 130 and 131, or polycrystalline silicon may be used for the channel portion of the TFT. Alternatively, a transistor may be formed on a semiconductor substrate such as silicon. Further, for example, MIS type elements may be used for the conversion units 124 and 1241. For example, the conversion unit 124 of the imaging pixel 110 may use a PIN diode, and the conversion unit 1241 of the detection pixel 111 may use an element having a different structure, such as an MIS type element. These combinations can be freely selected. What is necessary is just to select suitably according to the pixel, the element, and the circuit which are arranged outside the imaging region 107 and the imaging region 107 of the radiation detection apparatus 101.

  The switch element 130 of the imaging pixel 110 is formed on the substrate 100. In the present embodiment, the switch element 130 is formed in a layer below the first electrode 125, that is, a position closer to the substrate 100 than the first electrode 125. As shown in FIG. 4A, the gate insulating film 133 may cover the entire imaging pixel 110, or may cover only the gate electrode 132 of the switch element 130, for example. A protective film 134 and an interlayer insulating film 142 are formed on the switch element 130 so as to cover the switch element 130, the control line 150, and the signal line 160. The photoelectric conversion element 120 is formed on the interlayer insulating film 142. The photoelectric conversion element 120 includes a second impurity semiconductor layer having a conductivity type opposite to that of the first electrode 125, the first impurity semiconductor layer 127, the intrinsic semiconductor layer 128, and the first impurity semiconductor layer 127 from the side close to the substrate 100. 129 and the second electrode 126 are stacked in this order. The first impurity semiconductor layer 127, the intrinsic semiconductor layer 128, and the second impurity semiconductor layer 129 constitute a PIN photodiode and constitute the conversion unit 124. The first electrode 125 is connected to the drain electrode 135 of the switch element 130 via a contact plug C1 provided with a contact hole penetrating the protective film 134 and the interlayer insulating film 142. An insulating layer including the protective film 140 and the interlayer insulating film 143 is formed over the second electrode 126 so as to cover the photoelectric conversion element 120. On the interlayer insulating film 143, a bias line 190 extends in a direction parallel to the surface of the substrate 100, and is connected to the second electrode 126 via a contact plug C 2 provided on the protective film 140 and the interlayer insulating film 143. Connected. A protective film 141 is formed on the bias line 190. For the contact plugs C1 and C2, for example, a wiring made of a conductive member such as metal can be used.

  FIG. 4B is a cross-sectional view of the detection line passing pixel 112 between B and B ′ in FIG. 3. Compared to the imaging pixel 110 shown in FIG. 4A, it has a detection line 161 extending in a direction parallel to the surface of the substrate 100, and other parts may be the same as the imaging pixel 110. The detection line 161 is arranged on the side opposite to the first electrode 125 with respect to the second electrode 126. In the present embodiment, the detection line 161 extends on the insulating layer composed of the protective film 140 and the interlayer insulating film 143 on the second electrode 126 disposed on the first electrode 125. Covered with a protective film 141. As shown in FIG. 4A, the detection line 161 may be disposed on the same interlayer insulating film as the interlayer insulating film 143 on which the bias line 190 is disposed. The detection line 161 is farther from the surface of the substrate 100 than the second electrode 126 and is disposed on an insulating layer disposed on the second electrode 126. In the present embodiment, the detection line 161 of the detection line passing pixel 112 includes a position overlapping the second electrode 126 in a plan view with respect to the surface of the substrate 100.

  FIG. 4C is a cross-sectional view of the detection pixel 111 between C and C ′ in FIG. 3. The switch element 131 of the detection pixel 111 is formed on the substrate 100. In the present embodiment, the switch element 131 is formed in a layer below the third electrode 1251, that is, a position close to the substrate 100. As shown in FIG. 4C, the gate insulating film 133 may cover the entire detection pixel 111 as in the imaging pixel 110, or may cover only the gate electrode 1321 of the switch element 131, for example. A protective film 134 and an interlayer insulating film 142 are formed on the switch element 131 so as to cover the switch element 131, the control line 150, and the signal line 160. The photoelectric conversion element 121 is formed on the interlayer insulating film 142. The photoelectric conversion element 121 is stacked in the order of a third electrode 1251, a first impurity semiconductor layer 1271, an intrinsic semiconductor layer 1281, a second impurity semiconductor layer 1291, and a fourth electrode 1261 from the side close to the substrate 100. . The first impurity semiconductor layer 1271, the intrinsic semiconductor layer 1281, and the second impurity semiconductor layer 1291 form a PIN photodiode and form the conversion unit 1241. Here, the conversion unit 1241 may have the same configuration as the conversion unit 124 of the imaging pixels 110 and 112. The third electrode 1251 is connected to the drain electrode 1351 of the switch element 131 via a contact plug C3 provided in the protective film 134 and the interlayer insulating film 142. An insulating layer including the protective film 140 and the interlayer insulating film 143 is formed over the fourth electrode 1261 so as to cover the photoelectric conversion element 121 included in the conversion circuit. A bias line 190 extends on the interlayer insulating film 143 and is connected to the fourth electrode 1261 through a contact plug C2 provided in the protective film 140 and the interlayer insulating film 143. The detection line 161 is connected to the source electrode 1361 of the switch element 131 constituting the conversion circuit via a contact plug C4 provided in a contact hole penetrating the protective films 134 and 140 and the interlayer insulating films 142 and 143. A protective film 141 is formed on the detection line 161 and the bias line 190. Here, the interlayer insulating film 142 may be a planarizing film on the switch element between the pixels. The interlayer insulating film 143 can be a planarizing film on the photoelectric conversion elements between the pixels. For the contact plugs C3 and C4, for example, a wiring made of a conductive member such as metal can be used.

  Here, the effect of this embodiment will be described. In the detection line passing pixel 112, a parasitic capacitance between the detection line 161 and the first electrode 125 connected to the reading circuit 103 of the detection line passing pixel 112 via an insulating layer such as a protective film or an interlayer insulating film. Exists. In the radiation detection apparatus 101, photoelectric conversion occurs in the photoelectric conversion element of each pixel during radiation irradiation, and the potential of the first electrode 125 of each pixel varies. When the potential of the first electrode 125 of the detection line passing pixel 112 changes, the potential of the detection line 161 changes due to the crosstalk via the parasitic capacitance. For this reason, the output signal transmitted from the detection pixel 111 to the detection pixel readout circuit 104 fluctuates, and it becomes difficult to accurately acquire radiation irradiation information. A large number of detection line passing pixels 112 are arranged along the detection line 161. For this reason, the influence of crosstalk through the parasitic capacitance between the detection line 161 and the first electrode 125 is increased. The structure in which the detection line 161 and the first electrode 125 shown in Patent Document 1 are opposed to each other is easily affected by crosstalk because the parasitic capacitance between the detection line 161 and the first electrode 125 is large. In order to suppress this crosstalk, in this embodiment, the parasitic capacitance between the detection line 161 and the first electrode 125 is reduced in the detection line passing pixel 112.

  In the present embodiment, the detection line 161 extends on the second electrode 126 via an insulating layer including the protective film 140 and the interlayer insulating film 143. While the radiation detection apparatus 101 is operating, the second electrode 126 is maintained at a constant potential by the bias power source 105 and does not change in potential. The detection line 161 is positioned on the opposite side of the second electrode 126 from the first electrode. That is, by arranging the second electrode 126 between the detection line 161 and the first electrode 125, the detection line 161 is electrostatically shielded from the first electrode 125 whose potential varies individually in each pixel. . For this reason, in the detection line passing pixel 112, the parasitic capacitance between the detection line 161 and the first electrode 125 is reduced. As a result, crosstalk can be suppressed, and radiation irradiation information, particularly irradiation information during radiation irradiation can be accurately acquired.

  The configurations of the detection line passing pixel 112 and the detection pixel 111 for obtaining the above effect are not limited to this embodiment. Hereinafter, modified examples of the configuration of the detection line passing pixel 112 and the detection pixel 111 will be described.

  FIG. 5A shows a cross-sectional view of the detection line passing pixel 112 of the first modification of the present embodiment. The detection line 161 may be disposed on an insulating layer including a protective film or an interlayer insulating film different from the interlayer insulating film on which the bias line 190 is disposed. In the present modification, the detection line 161 is formed on an insulating layer composed of the protective film 141 and the interlayer insulating film 144. The detection line 161 is located in a layer above the insulating layer on which the bias line 190 is disposed, and is farther from the surface of the substrate 100 than the bias line 190. A protective film 145 is disposed on the detection line 161. At this time, the detection line 161 is connected to the source electrode 1361 of the switch element 131 through the contact plug C4 provided in the protective films 134, 140, 141 and the interlayer insulating films 142, 143, 144. In this modification, the distance between the detection line 161 and the first electrode 125 is longer than that in the first embodiment. For this reason, the parasitic capacitance is reduced as compared with the first embodiment. As a result, the effect of suppressing the crosstalk of this modification is greater than that of the first embodiment.

  FIG. 5B shows a cross-sectional view of the detection line passing pixel 112 of the second modification of the present embodiment. The detection line 161 is disposed on the opposite side of the second electrode 126 from the first electrode 125 and in a layer further above the second electrode 126 disposed on the first electrode 125. That's fine. As illustrated in FIG. 5B, the detection line 161 may be arranged so as to include a portion between the second electrodes 126 of the photoelectric conversion elements 120 of the pixels adjacent to each other in a plan view with respect to the surface of the substrate 100. In this case, the pixels located on both sides of the detection line 161 are the detection line passing pixels 112. The effect of suppressing the crosstalk of this modification is smaller than that of the first modification described above. However, the effect of electrostatic shielding by the second electrode 126 can be obtained. Further, compared to the first embodiment, the wiring on the photoelectric conversion element 120 is reduced, so that the aperture ratio of the pixel is improved and the sensitivity of the radiation detection apparatus 101 is improved. Not limited to this modification, at least one of the bias line 190 and the detection line 161 is not disposed at a position overlapping the photoelectric conversion element 120 in a plan view with respect to the surface of the substrate 100, thereby passing the detection line of the radiation detection apparatus 101. The aperture ratio of the pixel 112 is improved and the sensitivity is improved. Further, for example, the bias line 190 may be disposed between the second electrodes 126 of the photoelectric conversion elements 120 of adjacent pixels, and the detection line 161 may be disposed on the detection line passing pixel 112. In this case, the improvement of the aperture ratio and the effect of suppressing the crosstalk equivalent to the first embodiment can be obtained.

  FIG. 6 is a plan view of the periphery of the detection pixel 111 according to the third modification of the present embodiment. FIG. 6 shows one detection pixel 111 and three detection line passing pixels 112 arranged on both sides of the detection line 161 in the imaging region 107. FIGS. 7A to 7D are cross-sectional views taken from A-A ′ to D-D ′ in FIG. 6. A detection line 161 and a bias line 190 are arranged including a portion between the detection pixel 111 and the detection line passing pixel 112 adjacent to each other in a plan view with respect to the surface of the substrate 100. The detection line 161 is disposed on the bias line 190 with an insulating layer including the protective film 141 and the interlayer insulating film 144 interposed therebetween. Further, the detection line 161 and the bias line 190 may be arranged at positions overlapping in the plan view with respect to the surface of the substrate 100. In this modification, the detection line 161 is electrostatically shielded from the first electrode 125 not only by the second electrode 126 but also by the bias line 190. In addition, while the radiation detection apparatus 101 is operating, the bias line 190 is maintained at a constant potential by the bias power source, like the second electrode 126. As a result, the parasitic capacitance between the detection line 161 of the detection line passing pixel 112 and the first electrode 125 in the present modification is equivalent to that in the first modification, and the first modification is also effective in suppressing crosstalk. Equivalent effect is obtained. In addition, compared with the first embodiment, the first modified example, and the second modified example, this modified example improves the aperture ratio of the imaging pixel 110 and the detection line passing pixel 112, and thus the sensitivity of the radiation detection apparatus 101. Is further improved.

  FIG. 8A is an overall view schematically showing a radiation detection apparatus 1011 of the fourth modification example of the present embodiment. In the detection pixel 111, the switch element 131 may be omitted. Therefore, as shown in FIG. 8A, the detection pixel scanning circuit 106 and the detection pixel control line 108 are not necessary, and the configuration of the radiation detection apparatus is simplified as compared with the radiation detection apparatus 101 shown in FIG. it can. In this modification, the conversion circuit includes a photoelectric conversion element 121. FIG. 8B shows an equivalent circuit of the detection pixel 1110 of the radiation detection apparatus 1011. Compared with the detection pixel 111 of the radiation detection apparatus 101, the detection pixel 1110 of the radiation detection apparatus 1011 does not have the switch element 131, and the third electrode 1251 is directly connected to the detection line 161. FIG. 9 is a plan view of the periphery of the detection pixel 1110 of the fourth modification example of the present embodiment. FIG. 5C is a cross-sectional view taken along the line C-C ′ in FIG. Instead of the switch element 131, a conductive member 139 is disposed in a layer where the signal line 160 is disposed. The detection line 161 is connected to the third electrode 1251 through the contact plug C4, the conductive member 139, and the contact plug C3. Further, the conductive member 139 is not formed, a part of the third electrode 1251 is enlarged, and the detection line 161 and the third electrode 1251 are contact plugs (not shown) provided in the protective film 140 and the interlayer insulating film 143. ) May be connected directly. In this modification, the parasitic capacitance between the detection line 161 of the detection line passing pixel 112 and the first electrode 125 is equivalent to that of the first embodiment, and the effect of suppressing crosstalk is also the first embodiment. Is equivalent to

Second Embodiment With reference to FIGS. 10 to 12, the structure of a radiation detection apparatus according to a second embodiment will be described. 10A and 10B show equivalent circuits of the imaging pixel 110 and the detection pixel 111. FIG. In the detection pixel 111, the fourth electrode 1261 is connected to the detection line 161, and the source electrode 1361 of the switch element 131 is connected to the signal line 160, which is different from the first embodiment. An overall schematic diagram of the radiation detection apparatus 101 and an equivalent circuit of the imaging pixel 110 shown in FIG. 10A may be the same as those in FIGS. 1 and 2A of the first embodiment. Similarly to the first embodiment, the equivalent circuit of the detection line passing pixel 112 may be the same as that of the imaging pixel 110.

  The voltage applied between the first electrode 125 and the second electrode 126 of the photoelectric conversion element 120 is between the potential of the bias power source 105 and the reference potential of the readout circuit 103 as in the first embodiment. It is a potential difference. On the other hand, the voltage applied between the third electrode 1251 and the fourth electrode 1261 of the photoelectric conversion element 121 of the detection pixel 111 is the difference between the reference potential of the detection pixel readout circuit 104 and the reference potential of the readout circuit 103. The potential difference between. Also in this embodiment, in order to drive the photoelectric conversion elements 120 and 121 to perform the photoelectric conversion operation, these potential differences are set appropriately. FIG. 10C shows an example of an equivalent circuit of a charge readout method that can be used as the readout circuit 103 and FIG. 10D as the detection pixel readout circuit 104. The read circuit 103 may be the same as the read circuit shown in FIG. On the other hand, the detection pixel readout circuit 104 includes a power supply 2001 for adjusting the reference potential. In this embodiment, the voltage applied to the photoelectric conversion element 121 of the detection pixel 111 is a potential difference between the potential of the power supply 2001 that is the reference potential of the detection pixel readout circuit 104 and the GND potential that is the reference potential of the readout circuit 103. become.

  FIG. 11 is a plan view of the radiation detection apparatus 101 of the present embodiment, and FIGS. 12A to 12C are cross-sectional views from A-A ′ to C-C ′ in FIG. 11. As shown in FIG. 12C, in the detection pixel 111, the drain electrode 1351 of the switch element 131 is connected to the third electrode 1251 through a contact plug C5 provided in the protective film 134 and the interlayer insulating film 142. Is done. The fourth electrode 1261 is connected to the detection line 161 through a contact plug C6 provided in the protective film 140 and the interlayer insulating film 143. Further, the radiation detection apparatus 101 of this embodiment may not have a contact plug corresponding to the contact plug C4 used in the first embodiment. Other configurations of the detection pixel 111 and configurations of the imaging pixel 110 and the detection line passing pixel 112 shown in FIGS. 12A and 12B are the first embodiment shown in FIGS. 4A and 4B. May be the same. For the contact plugs C5 and C6, for example, a wiring made of a conductive member such as metal can be used.

  In this embodiment, the parasitic capacitance between the detection line 161 of the detection line passing pixel 112 and the first electrode 125 is equivalent to that of the first embodiment, and the effect of suppressing crosstalk is also the first implementation. It is equivalent to the form. On the other hand, in the present embodiment, the number of contact plugs arranged in the detection pixel 111 is smaller than that in the first embodiment. Further, the number of protective films and interlayer insulating films for opening contact holes for forming contact plugs is also small. For this reason, it is possible to reduce the number of manufacturing steps required for forming contact holes and contact plugs. As a result, the productivity of the radiation detection apparatus 101 can be improved and the manufacturing yield can be improved.

  Although the first and second embodiments have been described above, the present invention is not limited to these embodiments. Each embodiment and modification which were mentioned above can be changed and combined suitably. For example, each modification described in the first embodiment may be applied to the second embodiment.

  FIG. 13 is a schematic cross-sectional view of the arrangement of the radiation detection apparatus 101 described above with respect to the radiation source. In FIG. 13A, the radiation source 3001 emits, for example, X-rays 3003 toward the subject 3002. In the radiation detection apparatus 101, a scintillator 3004 that emits visible light by X-ray irradiation is disposed on the side of the photoelectric conversion elements 120 and 121 that faces the substrate 100. The scintillator 3004 emits light by the X-rays that have passed through the subject 3002, and the radiation detection apparatus 101 detects the X-rays 3003 by detecting this light in the photoelectric conversion elements 120 and 121. When the substrate 100 transmits X-rays 3003, it is preferable that the X-rays 3003 enter from the back side of the substrate 100 as shown in FIG. Even when the radiation source 3001 emits electromagnetic noise simultaneously with radiation such as the X-ray 3003, the detection line 161 of the detection line passing pixel 112 is electrostatically shielded from electromagnetic noise by the second electrode 126 of the detection line passing pixel 112. Is done. For this reason, the detection line 161 is not easily affected by electromagnetic noise from the radiation source 3001. As a result, the arrangement of the radiation detection apparatus 101 shown in FIG. 13B can acquire irradiation information with higher accuracy than the arrangement shown in FIG.

  Further, the detection pixels 111 can be freely arranged in the imaging region 107. For example, attention may be paid to a part of the imaging region 107, and the detection pixels 111 may be provided intensively in this region. As shown in FIG. 14A, a part of the area on the imaging area 107 may be a specific area 4001, and a plurality of detection pixels 111 may be arranged in the specific area 4001. The detection pixel 111 may not be arranged in an area other than the specific area 4001 in the imaging area 107. Further, a plurality of detection pixels 111 provided in the specific region 4001 may be further divided into a plurality of series including one or more detection pixels 111, and the detection pixels 111 may be read for each series. FIG. 14B shows an example of a timing diagram of voltages applied to the detection pixel control lines 108 of a plurality of series by the detection pixel scanning circuit 106. FIG. 15 is an example of an equivalent circuit of a portion 4002 surrounded by a broken line in FIG. In FIG. 15, the detection pixels 111 are divided into four series, and are driven for each series by a drive signal sent from the detection pixel scanning circuit 106 via the detection pixel control line 108 shown in FIG. Is done.

  In the specific region 4001, detection pixels 1111 belonging to the first series 4011, detection pixels 1112 belonging to the second series 4012, detection pixels 1113 belonging to the third series 4013, and detection pixels 1114 belonging to the fourth series 4014 are arranged. Has been. Each series of detection pixels 111 has a switch element 131, and a detection pixel control line 108 is commonly connected to the gate electrode of each series. The detection pixel scanning circuit 106 drives the detection pixels 111 for each series via the detection pixel control line 108. Depending on the arrangement of the detection pixels 111, the detection line 161 may intersect with a plurality of series of detection pixel control lines 108. In the present embodiment, the detection line 161 of the detection line passing pixel 112 is electrostatically shielded from the detection pixel control line 108 by the second electrode 126. For this reason, even if the potentials of the plurality of detection pixel control lines 108 change in a complex manner as shown in FIG. 14B while the irradiation information is acquired and transferred to the detection pixel readout circuit 104, the detection line 161 is It is difficult to be affected by the potential change of the detection pixel control line 108. Thereby, the radiation detection apparatus can acquire radiation irradiation information with high accuracy. In this example, the number of series is four, but the present invention is not limited to this. The number of series for reading the detection pixel 111 for each series may be 3 or less, or 5 or more.

  Hereinafter, a radiation detection system incorporating the radiation detection apparatus 101 of the present invention will be described as an example with reference to FIG. X-rays 6060 generated by an X-ray tube 6050 serving as a radiation source pass through a chest 6062 of a patient or subject 6061 and enter a radiation imaging apparatus 6040 using the radiation detection apparatus 101 of the present invention. This incident X-ray includes information inside the body of the patient or subject 6061. In the radiation imaging apparatus 6040, the scintillator emits light in response to the incidence of the X-ray 6060, and this is photoelectrically converted by the photoelectric conversion element of the radiation detection apparatus 101 to obtain electrical information. This information is converted into digital data, image-processed by an image processor 6070 as a signal processing unit, and can be observed on a display 6080 as a display unit of a control room. Further, this information can be transferred to a remote place by a transmission processing unit such as a telephone line 6090. In this way, it can be displayed on a display 6081 which is a display unit such as a doctor room in another place, and a doctor in a remote place can make a diagnosis. In addition, this information can be recorded on a recording medium such as an optical disk, and can also be recorded on a film 6110 serving as a recording medium by the film processor 6100.

DESCRIPTION OF SYMBOLS 100 Board | substrate, 101 Radiation detection apparatus, 104 Reading circuit for detection pixels, 105 Bias power supply, 107 Imaging area, 110 Imaging pixel, 111 Detection pixel, 120, 121 Photoelectric conversion element, 125 1st electrode, 126 2nd electrode, 140, 141 Protective film, 143, 144 Interlayer insulating film, 161 detection line, 190 bias line

Claims (19)

A radiation detection apparatus having an imaging region on a substrate having a first pixel for acquiring an image in which radiation is detected and a second pixel for acquiring radiation irradiation information,
The first pixel includes a first conversion element including a first electrode disposed on the substrate and a second electrode disposed on the first electrode;
The second pixel includes a conversion circuit including a second conversion element disposed on the substrate, which generates a signal based on radiation applied to the second pixel.
The radiation detection apparatus comprises:
A bias line for connecting the second electrode to a bias power source for driving the first conversion element;
A detection line for transmitting the signal generated by the second conversion element to a detection circuit outside the imaging region;
The radiation detection apparatus, wherein the detection line is arranged on the opposite side of the second electrode with respect to the second electrode. An insulating layer covering the first conversion element and the conversion circuit;
The radiation detection apparatus according to claim 1, further comprising a contact plug that penetrates the insulating layer and connects the conversion circuit and the detection line.   The radiation detection apparatus according to claim 2, wherein the detection line includes a portion that overlaps the second electrode of the first pixel in a plan view with respect to the surface of the substrate. The radiation detection apparatus includes a plurality of the first pixels,
4. The radiation according to claim 2, wherein the detection line includes a portion located between the second electrodes of the first pixels adjacent to each other in a plan view with respect to a surface of the substrate. Detection device.   The radiation detection apparatus according to claim 2, wherein the bias line is disposed on the insulating layer. The insulating layer includes a first insulating layer and a second insulating layer on the first insulating layer,
5. The radiation detection apparatus according to claim 2, wherein the bias line is disposed between the first insulating layer and the second insulating layer. 6.   The radiation detection apparatus according to claim 6, wherein the detection line includes a portion overlapping the bias line in a plan view with respect to the surface of the substrate. The second conversion element includes a third electrode disposed on the substrate, and a fourth electrode disposed on the third electrode,
The first electrode is connected to a readout circuit outside the imaging region to which the image is transferred, via a first switch element and a signal line.
The third electrode is connected to the detection circuit via the detection line and the contact plug,
The fourth electrode is connected to the bias power supply through the bias line,
8. The voltage according to claim 2, wherein a voltage corresponding to a difference between a potential of the bias power supply and a reference potential of the detection circuit is applied to the second conversion element. Radiation detection device.   The radiation detection apparatus according to claim 8, wherein the first switch element is disposed below the first electrode on the substrate.   The radiation detection apparatus according to claim 8 or 9, wherein a reference potential of the detection circuit and a reference potential of the readout circuit are equal to each other.   The radiation detection apparatus according to claim 8, wherein a reference potential of the detection circuit and a reference potential of the readout circuit are ground potentials.   The radiation detection apparatus according to claim 8, wherein the detection circuit and the readout circuit are an integrated circuit.   The radiation detection apparatus according to claim 8, wherein the third electrode is connected to the detection circuit via a second switch element and the detection line. The second conversion element includes a third electrode disposed on the substrate, and a fourth electrode disposed on the third electrode,
The first electrode is connected to a readout circuit outside the imaging area to which the image is transferred, via a first switch element and a first signal line.
The third electrode is connected to the readout circuit via a second signal line;
The fourth electrode is connected to the detection circuit via the detection line and the contact plug,
8. The voltage according to claim 2, wherein a voltage corresponding to a difference between a reference potential of the readout circuit and a reference potential of the detection circuit is applied to the second conversion element. Radiation detection equipment.   The radiation detection apparatus according to claim 14, wherein the first switch element is disposed below the first electrode on the substrate.   The radiation detection apparatus according to claim 14, wherein the third electrode is connected to the readout circuit via a second switch element and the second signal line.   The radiation detection apparatus according to claim 1, wherein the substrate is an insulating substrate.   The radiation detection apparatus according to claim 2, wherein the insulating layer is a planarization film that covers the first conversion element and the conversion circuit. A radiation detection apparatus according to any one of claims 1 to 18,
And a signal processing unit for processing a signal from the radiation detection apparatus.