Solid-state image pickup device and radiation image pickup device suitable for use in a flat panel detector

A solid-state image pickup device according to the present invention has a plurality of photoelectric conversion elements and a plurality of switching elements. The photoelectric conversion element is formed above at least one switching element, and a shielding electrode layer is disposed between the switching elements and the photoelectric conversion elements. Further, a radiation image pickup device according to the present invention has a radiation conversion layer for directly converting radiation into electric charges, and a plurality of switching elements, and has the radiation conversion layer formed above one or more switching elements, and a shielding electrode layer disposed between the switching elements and the radiation conversion layer.

TECHNICAL FIELD

The present invention relates in general to a radiation image pickup device for detecting radiation such as X-rays (but including within this term, for purposes of this application, beams of alpha or beta particles, as well as gamma rays), the device being applied to a medical image diagnosis system, a non-destructive inspection system, an analyzer or the like. More particularly, the invention relates to a solid-state image pickup device for use in a flat panel detector (hereinafter referred to as “an FPD” for short when applicable). The FPD is obtained by combining a sensor array constituted by a sensor device using non-monocrystalline silicon, e.g., amorphous silicon (hereinafter referred to as “a-Si” for short) and TFT elements, with a phosphor for converting radiation into visible rays of light, etc.

BACKGROUND ART

In recent years, the technique for TFTs for liquid crystal display devices has progressed, and servicing for information infrastructure has been made satisfactory. Thus, at the present time, the FPD is proposed, and even in the medical image field, the FPD can have a large area and digitization of the FPD is attained.

This FPD is adapted to read out a radiation image in an instant to display the image on a display device simultaneously, and an image can be directly fetched in the form of digital information from the FPD. Thus, the FPD has the feature that handling and management is convenient in the safekeeping of data, and in the processing and transfer of data. In addition, it was verified that though the characteristics such as sensitivity depend on photographing conditions, the characteristics are equal to or superior to those in a conventional screen film photographing method or a computed radiography photographing method.

Commercialization of the FPD has been attained. On the other hand, various proposals for the FPD have been made for the purpose of aiming at further enhancing the sensitivity. For example, in a paper by L. E. Antonuk et al., in the journalSPIE Medical Imaging VI, February, pp. 23 to 27, 1992, there is disclosed a structure in which a sensor element is formed on a TFT element. In this example, adoption of the above-mentioned structure allows an open area ratio of the sensor element to be increased to make enhancement of sensitivity possible.

In addition, it is described that since the TFT element is disposed right under the sensor element, an unnecessary parasitic capacitance is formed, and hence a grounded plane is provided.

In addition, in a proposal made in U.S. Pat. No. 5,498,880, granted to DuPont, likewise, there is shown a structure in which in order to increase an open area ratio, a sensor element is formed on a TFT element. In this example, there is adopted a structure in which an electrode connected to a source/drain electrode of the TFT covers the TFT element, and also serves as a separate electrode of the sensor element.

On the other hand, in a proposal in Japanese Patent Application Laid-Open No. 2000-156522, filed by Canon Kabushiki Kaisha, there is shown a structure in which for the purpose of aiming at increasing an open area ratio, a sensor element is formed above a TFT element. In this example, there is adopted a structure in which the sensor element is formed over the TFT element, but spaced from the latter by an interlayer film.

However, in the above-mentioned FPD having the sensor element formed on the TFT element, the separate electrode of the sensor element acts as a back gate electrode of the TFT element. Hence, a problem of generation of a leakage current of the TFT element is caused by the fluctuation in electric potential of the separate electrode. Such a problem appears in the form of degradation of quality of the image.

In a case where for example, an area having a large sensor output signal and an area having a small sensor output signal are disposed adjacent to each other, crosstalk that blurs the boundary between these areas appears. In addition, there is caused a problem that sensor saturation output is decreased, reducing the dynamic range.

SUMMARY OF THE INVENTION

The present invention has been made in the light of the foregoing problems, and it is, therefore, an object of the present invention to make it possible that even when an electric potential of a separate electrode of a sensor element disposed above a switching element fluctuates, the fluctuation in characteristics due to generation of a leakage current of the switching element is suppressed to attain enhancement of sensitivity.

In order to solve the above-mentioned problems, according to the present invention, there is provided a solid-state image pickup device including a plurality of photoelectric conversion elements and a plurality of switching elements, characterized in that the photoelectric conversion element is formed above at least one switching element, and a shielding electrode layer is disposed between the switching elements and the photoelectric conversion elements.

Further, according to the present invention, there is provided a radiation image pickup device including a radiation conversion layer for directly converting radiation into electric charges, and a plurality of switching elements, characterized in that the radiation conversion layer is formed above one or more switching elements, and a shielding electrode layer is disposed between the switching elements and the radiation conversion layer.

According to the present invention, the shielding layer is provided so as to be interposed between the switching element and the sensor portion formed above the switching element, whereby even when an electric potential of a separate electrode of the sensor element disposed above the switching element fluctuates, the fluctuation in characteristics due to generation of a leakage current of the switching element can be suppressed to attain enhancement of sensitivity.

BEST MODE FOR CARRYING OUT THE INVENTION

Description will hereinafter be given with respect to a solid-state image pickup device using a MIS type photodiode (hereinafter referred to as “a PD” for short when applicable) according to Embodiment 1 of the present invention.

FIG. 1is a schematic equivalent circuit diagram of pixels disposed in matrix of 3×3 of a solid-state image pickup device according to Embodiment 1,FIG. 2is a schematic plan view of one pixel of the solid-state image pickup device according to this embodiment,FIG. 3is a schematic plan view of four pixels of the solid-state image pickup device according to this embodiment, andFIG. 4is a schematic cross sectional view of the solid-state image pickup device according to this embodiment.

InFIGS. 1 and 2, reference numeral101designates a MIS type PD as a photoelectric conversion element (sensor element); reference numeral102designates a transferring TFT as a switching element (thin film transistor); reference numeral103designates a transferring TFT driving wiring; reference numeral104designates a signal line; reference numeral105designates a sensor biasing wiring; reference numeral106designates a shielding wiring (GND wiring); reference numeral107, a source/drain electrode layer of the transferring TFT102; reference numeral108, a contact hole; and109, a sensor lower electrode layer.

InFIG. 4, reference numeral110designates an insulating substrate made of glass or the like; reference numeral111designates a gate insulating film made of SiN, SiO2or the like; reference numeral112designates a first amorphous semiconductor layer made of a-Si or the like; reference numeral113designates a first n+type layer (ohmic contact layer); reference numerals114and115each designate an interlayer insulating film made of SiN, SiO2, benzocyclobutene (BCB), polyimide (PI) or the like; reference numeral116designates an insulating film made of SiN, SiO2or the like; reference numeral117, a second amorphous semiconductor layer made of a-Si or the like; reference numeral118, a second n+-type layer (hole blocking layer) made of microcrystalline silicon, a-Si or the like; reference numeral119, a transparent electrode layer made of ITO, SnO2or the like; reference numeral132, a passivation layer made of SiN, PI or the like; reference numeral134, an adhesion layer; and135, a phosphor layer acting as a wavelength conversion layer.

Note that, inFIG. 4, reference numerals103,105and106designate a gate electrode layer, a sensor biasing electrode layer, and a shielding electrode layer, respectively.

The insulating film116, the second amorphous semiconductor layer117made of a-Si or the like, and the second n+-type layer118constitute a photoelectric conversion layer of the MIS type PD101. The gate electrode layer103, the gate insulating film111made of SiN, SiO2or the like, the first amorphous semiconductor layer112made of a-Si or the like, the first n+-type layer (ohmic contact layer)113, and the source/drain electrode layer107for the transferring TFT constitute the transferring TFT102. The photoelectric conversion layer is formed above the transferring TFT102, and hence the transferring TFT102is covered with the photoelectric conversion layer.

The shielding electrode layer106is disposed so as to be interposed between the MIS type PD101and the transferring TFT102.

Radiation such as X-rays is made incident from above inFIG. 2, to be converted into visible rays of light through the phosphor layer135. The resultant rays are then converted into electric charges by the MIS type PD101to be accumulated in the MIS-type PD101. Thereafter, the transferring TFT102is operated by a TFT driving circuit through the transferring TFT driving wiring103to transfer these accumulated electric charges to the signal line104connected to one of the source electrode and the drain electrode of the transferring TFT102to be processed in the signal processing circuit, and the resultant analog signal is then subjected to A/D conversion in the A/D conversion circuit, to be outputted. In this processing the electric potential of the shielding wiring106is fixed to a constant electric potential such as GND at all times.

In this embodiment, the shielding wiring106disposed below the sensor element is grounded. As a result, even if the electric potential of a separate electrode of the sensor element fluctuates, fluctuation in characteristics due to generation of a leakage current of the TFT element can be suppressed, to allow enhancement of sensitivity to be attained. In addition, since the shielding wiring106does not overlap the signal line104at all, no parasitic capacitance is formed between the shielding wiring106and the signal line104, and hence degradation of the sensor sensitivity can also be suppressed.

In this embodiment, there has been shown the specific case where the width of the shielding wiring106is identical to the channel length of the TFT.

However, in order to reduce a capacitance in a cross portion between the transferring TFT driving wiring103and the shielding wiring106, it is also possible to use a wiring having a width smaller than the channel length in the cross portion between the transferring TFT driving wiring103and the shielding wiring106.

In addition, the shielding wiring106has only to be held at a constant electric potential, and hence it is also possible to set the electric potential of the shielding wiring106to any constant electric potential other than GND. Since the resistance of the shielding wiring106may be high, a wiring made of a high melting point metal such as molybdenum (Mo), chromium (Cr), titanium (Ti), tungsten (W), or molybdenum-tungsten (MoW) can be used as the shielding wiring106. This makes it possible to reduce limitations on the manufacturing process to be used. Moreover, of the layer including the gate electrode, the layer including the source/drain electrode, the layer including the shielding electrode, and the layer including the sensor biasing electrode, the shielding electrode layer is formed as the thinnest wiring in order to reduce a difference in level and to reduce a difference in level of the sensor portion formed above the shielding wiring106, resulting in improving the yield. This is because the electrical resistance value of the shielding electrode layer may be larger than that of each of other electrode layers.

Description will hereinafter be given with respect to a solid-state image pickup device using a MIS-type PD according to Embodiment 2 of the present invention.

FIG. 5is a schematic equivalent circuit diagram of pixels disposed in matrix of 3×3 of a solid-state image pickup device according to Embodiment 2,FIG. 6is a schematic plan view of one pixel of the solid-state image pickup device according to this embodiment,FIG. 7is a schematic plan view of four pixels of the solid-state image pickup device according to this embodiment, andFIG. 8is a schematic cross-sectional view of the solid-state image pickup device according to this embodiment.

The same reference numerals as those in Embodiment 1 indicate the same components.

InFIGS. 5 and 6, reference numeral101designates a MIS type PD; reference numeral102designates a transferring TFT; reference numeral103designates a transferring TFT driving wiring; reference numeral104designates a signal line; reference numeral105designates a sensor biasing wiring; reference numeral106designates a shielding wiring (GND wiring); reference numeral108, a contact hole; reference numeral109, a sensor lower electrode layer; reference numeral120, a resetting TFT as a switching element; reference numeral121, a resetting TFT driving wiring; and126, a reset wiring.

InFIG. 8, reference numeral110designates an insulating substrate made of glass or the like; reference numeral111designates a gate insulating film made of SiN, SiO2or the like; reference numeral112designates a first amorphous semiconductor layer made of a-Si or the like; reference numeral113designates a first n+-type layer (ohmic contact layer); reference numerals114and115each designate an interlayer insulating film made of SiN, SiO2, benzocyclobutene (BCB), polyimide (PI) or the like; reference numeral116designates an insulating film made of SiN, SiO2or the like; reference numeral117, a second amorphous semiconductor layer made of a-Si or the like; reference numeral118, a second n+-type layer (hole blocking layer) made of microcrystalline silicon, a-Si or the like; reference numeral119, a transparent electrode layer made of ITO, SnO2or the like; reference numeral107, a source/drain electrode layer of the transferring TFT102; reference numeral122, a source/drain electrode layer of the resetting TFT; reference numeral132, a passivation layer made of SiN, PI or the like; reference numeral134, an adhesion layer; and135, a phosphor layer.

Note that, inFIG. 8, reference numerals103and121each designate a gate electrode layer, reference numeral105designates a sensor biasing electrode layer, and reference numeral106designates a shielding electrode layer.

The insulating film116, the second amorphous semiconductor layer117made of a-Si or the like, and the second n+-type layer118constitute a photoelectric conversion layer of the MIS-type PD101. The gate electrode layer103, the gate insulating film111made of SiN, SiO2or the like, the first amorphous semiconductor layer112made of a-Si or the like, the first n+-type layer (ohmic contact layer)113, and the source/drain electrode layer107for the transferring TFT constitute the transferring TFT102. The gate electrode layer121, the gate insulating film111made of SiN, SiO2or the like, the first amorphous semiconductor layer112made of a-Si or the like, the first n+-type layer (ohmic contact layer)113, and the source/drain electrode layer122of the resetting TFT constitute the resetting TFT120. The photoelectric conversion layer is formed above the transferring TFT102and the resetting TFT120, and hence both the TFTs are covered with the photoelectric conversion layer.

The shielding electrode layer106is disposed so as to be interposed between the MIS type PD101and the transferring TFT102, and between the MIS-type PD101and the resetting TFT120.

Radiation such as X-rays is made incident from above inFIG. 6to be converted into visible rays of light through the phosphor layer135. The resultant rays are then converted into electric charges by the MIS-type PD101to be accumulated in the MIS-type PD101. Thereafter, the transferring TFT102is operated by the transferring TFT driving wiring103connected to a TFT driving circuit to transfer these accumulated electric charges to the signal line104connected to one of the source electrode and the drain electrode of the transferring TFT102to be processed in the signal processing circuit, and the resultant analog signal is then subjected to A/D conversion in the A/D conversion circuit, to be outputted. Thereafter, the resetting TFT120is operated by the resetting TFT driving wiring121connected to the signal processing circuit to reset the MIS-type PD101. In this processing the electric potential of the shielding wiring106is fixed to a constant electric potential such as GND at all times.

In this embodiment, the shielding wiring106disposed below the sensor element is grounded. As a result, even if the electric potential of a separate electrode of the sensor element fluctuates, fluctuation in characteristics due to generation of a leakage current of the TFT element can be suppressed, to allow enhancement of sensitivity to be attained. In addition, since the shielding wiring106does not overlap the signal line104at all, no parasitic capacitance is formed between the shielding wiring106and the signal line104, and hence degradation of the sensor sensitivity can also be suppressed.

In this embodiment, there has been shown the specific case where the width of the shielding wiring106is identical to the channel length of the TFT. However, in order to reduce the capacitance in a cross portion between the respective TFT driving wirings, it is also possible to use a wiring having a width smaller than the channel length in the cross portion between the respective TFT driving wirings.

Description will hereinafter be given with respect to a solid-state image pickup device using a MIS-type PD according to Embodiment 3 of the present invention.

FIG. 9is a schematic equivalent circuit diagram of pixels disposed in matrix of 3×3 of a solid-state image pickup device according to Embodiment 3,FIG. 10is a schematic plan view of one pixel of the solid-state image pickup device according to this embodiment,FIG. 11is a schematic plan view of four pixels of the solid-state image pickup device according to this embodiment, andFIG. 12is a schematic cross-sectional view of the solid-state image pickup device according to this embodiment.

The same reference numerals as those in Embodiment 1 indicate the same components.

InFIGS. 9 and 10, reference numeral101designates a MIS-type PD; reference numeral104designates a signal line; reference numeral105designates a sensor biasing wiring; reference numeral106designates a shielding wiring (GND wiring); reference numeral108designates a contact hole; reference numeral109designates a sensor lower electrode; reference numeral120designates a resetting TFT; reference numeral121designates a resetting TFT driving wiring; reference numeral123, a storage capacitor; reference numerals124and125designate a switching TFT and a reading TFT forming a source follower (“SFA”), respectively; reference numeral126, a reset wiring; reference numeral127, a contact hole through which the storage capacitor123and the shielding wiring106are connected to each other; reference numeral128, a switching TFT driving wiring; and130, a reading TFT driving electrode.

FIG. 12is a schematic cross-sectional view showing a part of the solid-state image pickup device indicated by an arrow inFIG. 10. Reference numeral110designates an insulating substrate made of glass or the like; reference numeral111designates a gate insulating film made of SiN, SiO2or the like; reference numeral112designates a first amorphous semiconductor layer made of a-Si or the like; reference numeral113designates a first n+-type layer (ohmic contact layer); reference numerals114and115each designate an interlayer insulating film made of SiN, SiO2, benzocyclobutene (BCB), polyimide (PI) or the like; reference numeral116designates an insulating film made of SiN, SiO2or the like; reference numeral117, a second amorphous semiconductor layer made of a-Si or the like; reference numeral118, a second n+-type layer (hole blocking layer) made of microcrystalline silicon, a-Si or the like; reference numeral119, a transparent electrode layer made of ITO, SnO2or the like; reference numeral122, a source/drain electrode layer of the resetting TFT; reference numeral129, a source/drain electrode layer of the switching TFT; reference numeral131, a source/drain electrode layer of the reading TFT; reference numeral132, a passivation layer made of SiN, PI or the like; reference numeral133, a contact hole; reference numeral134, an adhesion layer; and135, a phosphor layer.

Note that, inFIG. 12, reference numerals121,128, and130each designate a gate electrode layer, reference numeral105designates a sensor biasing electrode layer, and reference numeral106designates a shielding electrode layer.

The insulating film116, the second amorphous semiconductor layer117, and the second n+-type layer118constitute a photoelectric conversion layer of the MIS type PD101. The gate electrode layer121, the gate insulating film111made of SiN, SiO2or the like, the first amorphous semiconductor layer112made of a-Si or the like, the first n+-type layer (ohmic contact layer)113, and the source/drain electrode layer122for the resetting TFT constitute the resetting TFT120. The gate electrode layer128, the gate insulating film111made of SiN, SiO2or the like, the first amorphous semiconductor layer112made of a-Si or the like, the first n+-type layer (ohmic contact layer)113, and the source/drain electrode layer129of the switching TFT constitute the switching TFT124. The photoelectric conversion layer is formed above the resetting TFT120and the switching TFT124, and hence both the TFTs are covered with the photoelectric conversion layer.

The shielding electrode layer106is disposed so as to be interposed between the MIS-type PD101and the resetting TFT120, and between the MIS type PD101and the switching TFT124.

Radiation such as X-rays is made incident from above inFIG. 10to be converted into visible rays of light through the phosphor layer135. The resultant rays are then converted into electric charges by the MIS type PD101to be accumulated in the storage capacitor123through the contact holes108and133. Fluctuation in electric potential corresponding to these accumulated electric charges is caused in the gate electrode of the reading TFT125. Thereafter, the switching TFT124is operated through the switching TFT driving wiring128so that the accumulated electric charges are read out through the signal line104connected to one of the source electrode and the drain electrode of the reading TFT125to be processed in the signal processing circuit. The resultant analog signal is then subjected to A/D conversion in an A/D conversion circuit, to be outputted. Thereafter, the resetting TFT120is operated through the resetting TFT driving wiring121connected to the signal processing circuit to reset the storage capacitor123. In this processing the electric potential of the shielding wiring106is fixed to a constant electric potential such as GND at all times.

In this embodiment, the shielding wiring106disposed below the sensor element is grounded. As a result, even if the electric potential of a separate electrode of the sensor element fluctuates, fluctuation in characteristics due to generation of a leakage current of the TFT element can be suppressed, to allow enhancement of sensitivity to be attained. In addition, since the shielding wiring106does not overlap the signal line104at all, no parasitic capacitance is formed between the shielding wiring106and the signal line104, and hence degradation of the sensor sensitivity can also be suppressed.

In this embodiment, there has been shown the specific case where the shielding wiring portion is disposed above the two TFT portions and the storage capacitor portion. However, it is also possible to dispose the shielding wiring portion above three TFT portions and the storage capacitor portion.

In each of Embodiments 1 to 3 of the present invention described above, there has been shown specific cases where, in the indirect type solid-state image pickup device, the MIS-type PD is used as the photoelectric conversion element. However, it is also possible to use a PIN-type PD. In case of the PIN-type PD, the photoelectric conversion layer includes a p+-type layer, a second amorphous semiconductor layer, and a second n+-type layer instead of the insulating film116, the second amorphous semiconductor layer117, and the second n+-type layer118, respectively.

Description will hereinafter be given with respect to a direct type radiation image pickup device according to Embodiment 4 of the present invention.

FIG. 13is a schematic cross-sectional view of a direct type radiation image pickup device. Reference numeral110designates an insulating substrate made of glass or the like; reference numeral111designates a gate insulating film made of SiN, SiO2or the like; reference numeral112designates a first amorphous semiconductor layer made of a-Si or the like; reference numeral113designates an n+-type layer (ohmic contact layer); reference numerals114and115each designate an interlayer insulating film made of SiN, SiO2, benzocyclobutene (BCB), polyimide (PI) or the like; reference numeral120designates a resetting TFT; reference numeral123designates a storage capacitor; reference numerals124and125designate a switching TFT and a reading TFT forming a source follower (SFA), respectively; reference numeral121designates a resetting TFT driving wiring; reference numeral122, a source/drain electrode layer of the resetting TFT; reference numeral129, a source/drain electrode layer of the switching TFT; reference numeral128, a switching TFT driving wiring; reference numeral130, a reading TFT driving electrode; reference numeral131, a source/drain electrode layer of the reading TFT; reference numeral132, a passivation layer made of SiN, PI or the like; reference numeral133, a contact hole; and reference numeral145, a radiation conversion layer for directly converting radiation into electric charges.

A circuit diagram of the radiation image pickup device shown inFIG. 13is the same as that ofFIG. 1except that the radiation conversion layer145is used instead of the MIS-type photodiode101. In the direct type radiation image pickup device, a-Se, GaAs, CdTe or the like is used as a material of the radiation conversion layer.

Note that, inFIG. 13, reference numerals121,128and130each designate a gate electrode layer, reference numeral105designates a sensor biasing electrode layer, and reference numeral106designates a shielding electrode layer.

A layer structure of the resetting TFT120and the reading TFT124is the same as that in Embodiment 3. The radiation conversion layer145is formed above the resetting TFT120and the reading TFT124, and hence both the TFTs120and124are covered with the radiation conversion layer145.

Further, the shielding electrode layer106is disposed so as to be interposed between the radiation conversion layer145and the resetting TFT120, and between the radiation conversion layer145and the switching TFT124.

Radiation such as X-rays is made incident from an upper side of the radiation conversion layer shown inFIG. 13, to be directly converted into electric charges through the radiation conversion layer145. The resultant electric charges are then accumulated in the storage capacitor123through the contact holes108and133. Fluctuation in electric potential corresponding to the accumulated electric charges is caused in the gate electrode of the reading TFT125. Thereafter, the switching TFT124is operated through the switching driving wiring128so that the accumulated electric charges are read out through the signal line104connected to one of the source electrode and the drain electrode of the reading TFT125to be processed in a signal processing circuit. The resultant analog signal is then subjected to A/D conversion in an A/D conversion circuit, to be outputted. Thereafter, the resetting TFT120is operated through the resetting TFT driving wiring121connected to the signal processing circuit to reset the storage capacitor123. In this processing the electric potential of the shielding wiring106is fixed to a constant electric potential such as GND at all times.

While above, the embodiments of the present invention have been described, additional preferred embodiment modes of the present invention will now be enumerated as follows.

A solid-state image pickup device including a plurality of photoelectric conversion elements and a plurality of switching elements, in which the photoelectric conversion element is formed above at least one switching element, and a shielding electrode layer is disposed between the switching elements and the photoelectric conversion elements.

A solid-state image pickup device according to Embodiment Mode 1, in which one photoelectric conversion element and one or more switching elements are disposed in one pixel.

A solid-state image pickup device according to Embodiment Mode 1 or 2, in which the photoelectric conversion element has a photoelectric conversion layer, and the photoelectric conversion layer includes an insulating layer, a semiconductor layer, and a high impurity concentrated semiconductor layer.

A solid-state image pickup device according to Embodiment Mode 1 or 2, in which the photoelectric conversion element has a photoelectric conversion layer, and the photoelectric conversion layer includes a first high impurity concentrated semiconductor layer of one conductivity type, a semiconductor layer, and a second high impurity concentrated semiconductor layer of a conductivity type opposite to the one conductivity type of the first high impurity concentrated semiconductor layer.

A solid-state image pickup device according to any one of Embodiment Modes 1 to 4, in which the shielding electrode layer is not formed above a signal line connected to one of a source electrode and a drain electrode of the switching element.

A solid-state image pickup device according to any one of Embodiment Modes 1 to 5, in which the shielding electrode layer is held at a constant electric potential.

A solid-state image pickup device according to Embodiment Mode 6, in which the shielding electrode layer is grounded.

A solid-state image pickup device according to any one of Embodiment Modes 1 to 7, in which each of the switching elements is constituted by a TFT, and the shielding electrode layer is disposed so as to cover an upper portion of a channel of each of the TFTs.

A solid-state image pickup device according to Embodiment Mode 8, in which the shielding electrode layer has a width equal to or smaller than the channel length of the TFT and is disposed so as to cross a TFT driving wiring.

A solid-state image pickup device according to any one of Embodiment Modes 1 to 9, in which the shielding electrode layer is made of a high melting point metal.

A solid-state image pickup device according to Embodiment Mode 10, in which the shielding electrode layer is made of molybdenum (Mo), chromium (Cr), titanium (Ti), tungsten (W), or molybdenum-tungsten (MoW).

A solid-state image pickup device according to Embodiment Mode 1, in which the shielding electrode layer is an electrode layer thinner than each of a gate electrode layer, a source/drain electrode layer, and a sensor biasing electrode layer.

A solid-state image pickup device according to Embodiment Mode 1, in which the solid-state image pickup device includes a gate electrode layer, a gate insulating layer, a first amorphous semiconductor layer, a first n-type semiconductor layer, a source/drain electrode layer, a first interlayer insulating layer, the shielding electrode layer, a second interlayer insulating layer, a sensor lower electrode layer, an insulating layer, a second amorphous semiconductor layer, a second n-type semiconductor layer, a transparent electrode layer, and a sensor biasing electrode layer.

A solid-state image pickup device according to Embodiment Mode 13, in which one photoelectric conversion element and one or more TFTs are disposed in one pixel.

A radiation image pickup device, in which a wavelength conversion unit is disposed above the photoelectric conversion element in the solid-state image pickup device as described in any one of Embodiment Modes 1 to 9.

A radiation image pickup device according to Embodiment Mode 15, in which one photoelectric conversion element and one or more switching elements are disposed in one pixel.

A radiation image pickup device including a radiation conversion layer for directly converting radiation into electric charges, and a plurality of switching elements, in which the radiation conversion layer is formed above one or more switching elements, and a shielding electrode layer is disposed between the switching elements and the radiation conversion layer.

A radiation image pickup device according to Embodiment Mode 17, in which the radiation image pickup device includes a gate electrode layer, a gate insulating layer, a first amorphous semiconductor layer, a first n-type semiconductor layer, a source/drain electrode layer, a first interlayer insulating layer, the shielding electrode layer, a second interlayer insulating layer, a sensor lower electrode layer, a radiation conversion layer, and a sensor biasing electrode layer.

As set forth hereinabove, according to the present invention, even if fluctuation in electric potential of the separate electrode of the sensor element is caused, the fluctuation in characteristics due to generation of a leakage current of the switching element can be suppressed by provision of the shielding wiring disposed below the sensor element, to allow enhancement of sensitivity to be attained. Moreover, since the shielding wiring does not overlap the signal line at all, a parasitic capacitance formed between the shielding wiring and the signal line can be reduced to allow the degradation as well of the sensor sensitivity to be suppressed.

In addition, the shielding wiring having a width smaller than the channel length is used in the cross portion between the shielding wiring and the driving wiring of the switching element to allow the gate wiring capacitance also to be reduced.