KR20180044678A - Digital x-ray detector - Google Patents

Abstract

In the present invention, a fill factor can be increased by minimizing the reduction of an aperture ratio by a bias line by arranging the bias line to apply a bias voltage or a reverse bias voltage to a PIN diode in a region between two adjacent photo-sensing pixels. The bias line overlaps the two adjacent photo-sensing pixels so that the bias line is connected to a second electrode of a photo conductor. A connection pattern is extended from the bias line so that the bias line is connected to the second electrode of the photo conductor.

Description

[0001] DIGITAL X-RAY DETECTOR [0002]

The present invention relates to a digital x-ray detection apparatus having an improved fill factor.

X-rays can easily penetrate the subject with a short wavelength, and the amount of x-rays transmitted is determined by the density inside the subject. Therefore, the internal structure of the subject can be observed by detecting the amount of transmitted X-rays.

Generally, there is a disadvantage in that the film-printing x-ray method widely used in medical applications is required to undergo a printing process after taking a film, so that the result can be recognized after a certain period of time. There were many problems.

In order to solve such a problem, a digital X-ray detector (DXD) using digital data has recently been proposed. Conventional analog X-ray detecting apparatuses have a separate film to photograph a subject and transfer the photographed film to a photo paper. In contrast, a digital X-ray detecting apparatus displays an internal structure of a subject without using a separate film and a photo paper. That is, in the digital X-ray detecting apparatus, after converting the X-ray passing through the subject into light in the visible light region, the light in the converted visible light region is converted into an electronic signal, Display.

Such a digital X-ray detecting apparatus is provided with a photoconductor having a plurality of photo-sensing pixels and converting an electric signal inputted into each photo-sensing pixel, and a thin film transistor for outputting an electric signal to the outside.

The photoconductor includes a PIN diode and upper and lower electrodes. By applying a bias voltage or a reverse bias voltage to the PIN diode, the intrinsic semiconductor layer of the PIN diode is depleted by the P-type semiconductor layer and the N- And the holes and electrons generated by the light are drifted by the electric field to be collected in the p-type semiconductor layer and the n-type semiconductor layer, respectively, and current is generated.

However, in the digital X-ray detecting apparatus having such a structure, the performance of the detecting device is determined according to the fill factor. However, there has been a problem that the fill factor decreases depending on the structure of the photodetecting pixel and the structure of the photoconductor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved digital x-ray detection device with a fill filter.

In order to achieve the above object, the present invention improves the aperture factor of the photo-sensing pixel to improve the fill factor.

To this end, a thin film transistor having an oxide semiconductor layer is used in the present invention. Since the area of the thin film transistor having the oxide semiconductor layer is smaller than that of the thin film transistor having the amorphous silicon layer, the area occupied by the thin film transistor in the photo sensing pixel is reduced to improve the aperture ratio of the photo sensing pixel, Thereby improving the fill factor of the device.

In addition, in the present invention, by arranging a bias line for applying a bias voltage or a reverse bias voltage to the PIN diode in a region between two adjacent photo-sensing pixels, it is possible to minimize the aperture ratio reduction by the bias line, thereby improving the fill factor .

A bias line disposed in an area between two adjacent photo-sensing pixels overlaps a part of the photo-sensing pixel and a contact hole is formed in an overlapping area so that the bias line is electrically connected to the second electrode of the photoconductor, A bias voltage or a reverse bias voltage can be applied.

The bias line is formed to have a smaller width than the interval between the adjacent two photo-sensing pixels, and a separate connection pattern extends from the bias line to the adjacent two photo-sensing pixels, And may be electrically connected to the second electrode of the conductor to apply a bias voltage or a reverse bias voltage to the photoconductor.

In the digital X-ray detecting apparatus according to the present invention, two light sensing pixel columns share one bias line, thereby improving the aperture ratio of the photo-sensing pixels and improving the fill factor of the digital X-ray detector.

Further, in the present invention, since the oxide semiconductor is used as the semiconductor layer of the thin film transistor, the size of the thin film transistor can be reduced, so that the fill factor can be further improved.

Further, by using the oxide semiconductor as the semiconductor layer of the thin film transistor, the driving power can be reduced and the electric mobility can be improved. Therefore, it is possible to reduce the noise and to detect the moving picture x-ray according to the fast reading of the data.

1 is a plan view schematically showing a structure of a digital X-ray detecting apparatus according to the present invention.
2 is a circuit diagram of a photo-sensing pixel of a digital X-ray detector according to the present invention.
3 is a plan view showing a structure of a photo-sensing pixel of a digital X-ray detector according to a first embodiment of the present invention.
4 is a sectional view taken along the line I-I 'of FIG. 3;
5 is a plan view of a digital X-ray detecting device having a structure in which a bias line is disposed in a light-sensing pixel.
6 is a plan view showing the structure of a photo-sensing pixel of a digital X-ray detector according to a second embodiment of the present invention.
7A to 7D are views showing a manufacturing method of a digital X-ray detecting apparatus according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view of a digital X-ray detecting apparatus according to a first embodiment of the present invention, and FIG. 2 is a circuit diagram of a photo-sensing pixel of a digital X-ray detecting apparatus according to a first embodiment of the present invention.

1 and 2, the digital X-ray detecting apparatus according to the first embodiment of the present invention includes an X-ray detecting panel 110, a gate driving unit 130, a lead-out circuit unit 160, a timing control unit 170 And a bias voltage supply unit 150 are included.

The detection panel 110 senses the x-rays emitted from the light source, photoelectrically converts the sensed signal, and outputs the sensed signal as an electrical detection signal. A plurality of photo-sensing pixels P are disposed on the detection panel 110. [ At this time, the photo-sensing pixels P are defined by a plurality of gate lines GL arranged in the horizontal direction and a plurality of data lines DL arranged in the vertical direction.

The photo-sensing pixel P senses an input X-ray and outputs an electrical signal. As shown in FIG. 2, each photo-sensing pixel P includes a photoconductor PC that senses an X-ray and converts it into an electrical signal such as a detection voltage, and a photoelectric converter PC that charges the detection voltage converted by the photoconductor PC And a thin film transistor (TFT) which is driven in response to the application of the gate signal and transfers an electric signal such as a detection voltage stored in the capacitor Cst to the outside.

The photoconductor PC is made of a material capable of converting an X-ray emitted from the X-ray generator into an electrical signal. The photoconductor PC may be composed of, for example, a-Se, HgI ₂ , CdTe, PbO, PbI ₂ , BiI ₃ , GaAs, Ge,

The capacitor Cst charges the electrical signal converted by the photoconductor PC. The capacitor Cst has one end connected to the source electrode of the thin film transistor TFT and the other end connected to the bias line VL. In the thin film transistor TFT, a gate electrode is connected to a gate line GL for applying a scan signal, a drain electrode is connected to a data line DL for transmitting a detection signal, and a source electrode is connected to one end of a capacitor Cst do.

The gate driver 130 sequentially outputs a gate signal having a gate-on voltage level through a gate line GL. Here, the gate-on voltage level is a voltage level capable of turning on the thin film transistor of the photo-sensing pixel P, and the thin film transistor of the photo-sensing pixel P responds to the gate signal .

The gate driver 130 may be mounted on an external substrate (for example, an FPC (Flexible Printed Circuit Board)) directly mounted on the detection panel 110 or connected to the detection panel 110 in the form of an IC However, various devices such as transistors may be directly stacked on the detection panel 110 in the form of a GIP (Gate In Panel) through a photolithography process.

The bias voltage supply unit 150 supplies a bias voltage or a reverse bias voltage to the photosensitive pixel P through the bias line VL. At this time, the bias line VL is supplied with a voltage corresponding to a ground voltage (or a common voltage).

The lead-out circuit unit 160 reads out the detection signal output from the thin film transistor (TFT) turned on in response to the gate signal. As the thin film transistor TFT is turned on, a detection signal stored in the capacitor Cst is input to the lead-out circuit unit 160 through the thin film transistor TFT and the data line DL.

The lead-out circuit unit 160 includes an offset lead-out period for reading out an offset image and an x-ray lead-out period for reading out a detection signal output from the photo-sensing pixel P after the X-ray exposure. The readout circuit unit 160 may include a signal detection unit, a multiplexer, and the like. In addition, the signal detecting unit includes a plurality of amplifying circuit units corresponding one-to-one with the data lines DL, and each amplifying circuit unit may include an amplifier, a capacitor, a reset device, and the like.

The timing controller 180 generates a control signal and outputs the control signal to control the gate driver 130 and the readout circuit 160. The control signal supplied to the gate driver 130 may include a start signal STV and a clock signal CPV. The control signal supplied to the readout circuit 160 may be a readout control signal ROC, And a readout clock signal CLK.

3 is a diagram showing the structure of a photo-sensing pixel P of a digital X-ray detector according to the first embodiment of the present invention. Although the photo-sensing pixels P are arranged in a matrix form in the longitudinal and lateral directions substantially within the detection panel, n x m (where n and m are natural numbers) are arranged. In the figure, for convenience of explanation, Only the sensing pixels P1 and P2 are shown.

3, a plurality of gate lines GL and a plurality of data lines DL are vertically arranged to define a plurality of photo-sensing pixels P1 and P2, A thin film transistor (TFT) is arranged in the regions P1 and P2.

In this case, the data line DL is disposed on the left side of the odd-numbered light sensing pixel P1, the right-hand side of the data line DL on the even-numbered row light sensing pixel P2, The data lines DL are not disposed between the light sensing pixels P2 in the even-numbered columns and are spaced a certain distance a. Accordingly, one data line DL is disposed on the left side of the photosensitive pixel P1 of the first odd column, but two data lines DL are arranged between the photosensitive pixel P2 of the first even column and the photosensitive pixel P1 of the second odd column. (DL).

Each thin film transistor TFT is activated by applying gate signals to the gate electrodes 211a and 211b and gate electrodes 211a and 211b connected to the gate line GL and receiving a gate signal from the outside, And a detection voltage connected to the data line DL and stored in the capacitor Cst detected as the semiconductor layers 212a and 212b are activated, And source electrodes 214a and 214b and drain electrodes 215a and 215b that output the data signal to the data lines.

Photoconductors PC1 and PC2 are respectively provided in adjacent photo-sensing pixels P1 and P2. The photoconductors PC1 and PC2 detect light incident thereon and convert the light into electrical signals such as a detection voltage. The photoconductors PC1 and PC2 are formed over the entire area of the photosensitive pixels P1 and P2. The photoconductors PC1 and PC2 can be any structure as long as they can convert light into electrical signals. In the present invention, photodiodes are mainly used as photoconductors PC1 and PC2. In other words, in the present invention, as the photoconductors PC1 and PC2, a photodiode having PIN diodes 254a and 244b made of a P-type semiconductor layer, an intrinsic semiconductor layer, and an N-type semiconductor is used.

First electrodes 252a and 252b and second electrodes 256a and 256b are disposed on upper and lower portions of respective PIN diodes 254a and 254b disposed in adjacent photo-sensing pixels P1 and P1. Although the first electrodes 252a and 252b and the second electrodes 256a and 256b are formed substantially in the same area as the PIN diodes 254a and 254b and are disposed in the respective photosensitive pixels P1 and P1, In the figure, the first electrodes 252a and 252b, the second electrodes 256a and 256b, and the PIN diodes 254a and 254b are illustrated with different areas for convenience of explanation.

Since the first electrodes 252a and 252b and the second electrodes 256a and 256b and the PIN diodes 254a and 254b are disposed only in the corresponding photo sensing pixels P1 and P2, P1. ≪ / RTI > In other words, the photoconductors PC1 and PC2 of the adjacent photodetecting pixels P1 and P1 are configured to be separated from each other, and independently convert the incident light into a current.

A bias line VL having a predetermined width is disposed on the second electrodes 256a and 256b to apply a bias voltage or a reverse bias voltage to the PIN diodes 254a and 256b. The bias VL is disposed between two adjacent photodetecting pixels P1 and P1 and the width d1 of the photodetecting pixel P1 is set to a region between adjacent photodetecting pixels P1 and P2, (D> a) between the photoconductors PC1 and PC2 disposed in the sensing pixels P1 and P2 respectively and a part of the bias line VL is set to be adjacent to the adjacent photodetecting pixels P1 and P2, P2.

Although not shown in the figure, an insulating layer is provided between the second electrodes 256a and 256b and the bias line VL, and the first contact hole 264a and the second contact hole 264b are connected to the adjacent photo- The bias line VL is formed under the bias line VL extending to the pixels P1 and P2 so that the bias line VL is electrically connected to two adjacent second electrodes VL through the first contact hole 264a and the second contact hole 264b. Second and third electrodes 256a and 256b which are electrically connected to the first and second photo sensing pixels P1 and P2 via the bias line VL and are electrically connected to the first electrodes 256a and 256b, .

As described above, in the first embodiment of the present invention, the bias lines VL are arranged in the longitudinal direction, that is, substantially parallel to the data lines DL, A voltage or a reverse bias voltage is applied. In this case, since one bias line VL is shared by two neighboring photodetection pixels P1 and P2, for example, in the case of a digital X-ray detecting device having m photodetecting pixel columns, m / 2 bias lines .

Although not shown in the drawings, a scintillator is provided on the PIN diodes 254a and 254b. The scintillator layer collides with the input x-ray and emits light, thereby converting the x-ray into light in the visible light region and outputting the light.

When the X-ray transmitted through the subject is incident, the X-ray inputted from the scintillator layer is converted into light in the visible ray region and outputted, and the output light in the visible ray region passes through the PIN diode 254a , 254b. As the light is input, the intrinsic semiconductor layers of the PIN diodes 254a and 254b are depleted by the P-type semiconductor layer and the N-type semiconductor layer, and an electric field is generated therein. Are drifted by the electric field and are collected in the P-type semiconductor layer and the N-type semiconductor layer, respectively, to generate a current.

When a gate signal is applied to the thin film transistor TFT through the gate line GL and the thin film transistor TFT is turned on, a current generated in the PIN diodes 254a and 254b is applied to the first electrodes 252a and 252b And is output to the outside as a detection signal through the thin film transistor (TFT). The output detection signal is input to the readout circuit unit 160 and is read out.

As described above, in the digital X-ray detecting apparatus according to the first embodiment of the present invention, the X-rays input from the plurality of photo-sensing pixels P1 and P2 are converted into electrical signals and output, One X-ray can be read out.

Therefore, as compared with the conventional analog X-ray detecting apparatus, there is no need for a separate film and a photo paper, and there is no need to store and store the film after photographing. In addition, the detection signal of the photographed X-ray can be read out in real time, and the inspection of the internal structure of the subject can be performed quickly.

Hereinafter, a digital X-ray detecting apparatus according to a first embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 4 is a cross-sectional view taken along the line I-I 'of FIG. 3, showing the structure of two adjacent photo-sensing pixels P1 and P2 of the digital X-ray detector according to the first embodiment of the present invention.

As shown in FIG. 4, a buffer layer 221 is disposed on a transparent substrate 210 such as glass or plastic, and thin film transistors TFT1 and TFT2 are disposed thereon. At this time, the buffer layer 221 is formed of an inorganic insulating material, and may be a single layer or a plurality of layers.

Each of the thin film transistors TFT1 and TFT2 includes semiconductor layers 212a and 212b disposed on a buffer layer 221, a gate insulating layer 223 on which the semiconductor layers 212a and 212b are disposed, Gate electrodes 211a and 211b disposed on the interlayer insulating layer 223 and an interlayer insulating layer 223 provided in a region where the thin film transistor of the substrate 210 is formed; And source electrodes 214a and 214b and drain electrodes 215a and 215b which are in contact with the source and drain regions of the semiconductor layers 212a and 212b through contact holes formed in the source and drain electrodes 223 and 223, respectively.

The semiconductor layers 212a and 212b may be formed of an amorphous semiconductor such as amorphous silicon or an oxide semiconductor such as IGZO (Indium Gallium Zinc Oxide), TiO ₂ , ZnO, WO ₃ , or SnO ₂ . When the semiconductor layers 212a and 212b are formed of an oxide semiconductor, the size of the thin film transistors TFT1 and TFT2 can be reduced, the driving power can be reduced, and the electric mobility can be improved. Accordingly, it is possible not only to improve the fill factor of the digital X-ray detecting apparatus and to reduce the noise, but also to detect the moving picture x-ray according to the fast data reading.

Of course, the semiconductor layer of the thin film transistor of the digital x-ray inspection apparatus according to the first embodiment of the present invention is not limited to the oxide semiconductor material, but all types of semiconductor materials currently used in the thin film transistor may be used.

The source and drain electrodes 214a and 214b and the drain electrodes 215a and 215b are formed in the channel region of the central region and the source region and the drain region, Respectively. The gate electrodes 211a and 211b may be formed of a metal such as Cr, Mo, Ta, Cu, Ti, Al, or an Al alloy, or an alloy thereof.

The gate insulating layer 222 may be a single layer made of an inorganic insulating material such as SiOx or SiNx or a double layer made of SiOx and SiNx. Although the gate insulating layer 222 is disposed only under the gate electrodes 211a and 211b in the drawing, the gate insulating layer 222 may be stacked over the entire substrate 210. [

The source electrodes 214a and 214b and the drain electrodes 215a and 215b are formed of a metal such as Cr, Mo, Ta, Cu, Ti, Al, Al alloy, or an alloy thereof. The first interlayer insulating layer 223, And contact holes formed in the second interlayer insulating layer 224 and the source and drain regions of the semiconductor layers 212a and 212b, respectively. The interlayer insulating layer 223 may be formed of an inorganic material such as SiOx or SiNx.

A first passivation layer 225 is provided on a substrate 210 provided with a thin film transistor and the first passivation layer 225 is provided with first electrodes 252a and 252b, PIN diodes 254a and 254b, And the second electrodes 256a and 256b are disposed. The first electrodes 252a and 252b, the PIN diodes 254a and 254b and the second electrodes 256a and 256b form photoconductors PC1 and PC2 to convert incident light into an electrical signal.

The first electrodes 252a and 252b may be made of MoTi. However, the first electrodes 252a and 252b may be formed of various metals having good conductivity. The first electrodes 252a and 252b may be formed of a transparent metal oxide such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The second electrodes 256a and 256b may be formed of a transparent metal oxide such as ITO or IZO.

The PIN diodes 254a and 254b are formed by sequentially laminating an N-type semiconductor layer, an intrinsic semiconductor layer, and a P-type semiconductor layer from the first electrodes 252a and 252b. When the bias voltage or the reverse bias voltage is applied to the first electrodes 252a and 252b and the second electrodes 256a and 256b, holes and electrons are generated in the intrinsic semiconductor layer and holes are generated in the P- And electrons move to the N-type semiconductor layer and a current is outputted through the first electrodes 252a and 252b.

Although amorphous silicon (a-Si) is mainly used as a semiconductor for forming the N-type semiconductor layer, the intrinsic semiconductor layer and the P-type semiconductor layer, the present invention is not limited to such a material but HgI ₂ , CdTe, PbO, PbI ₂ , BiI ₃ , GaAs, Ge, and the like can be used.

In addition, the first passivation layer 225 may be formed of an organic insulating material such as photo-acryl or an inorganic insulating material such as SiOx or SiNx. The first passivation layer 225 may be formed of a plurality of layers including an organic insulating layer / an inorganic insulating layer, an inorganic insulating layer / an organic insulating layer / an inorganic insulating layer.

A second passivation layer 226 is deposited on the substrate 210 provided with the photocontactors PC1 and PC2. The second passivation layer 226 may be formed of an organic insulating material such as photoacryl or an inorganic insulating material such as SiOx or SiNx. In addition, the second passivation layer 226 may be formed of a plurality of layers including an organic insulating layer / an inorganic insulating layer, an inorganic insulating layer / an organic insulating layer / an inorganic insulating layer.

A bias line (VL) is disposed on the second protective layer (226). Since the width d1 of the bias line VL is greater than the interval between the photoconductors PC1 and PC2 disposed at the adjacent photodetecting pixels P1 and P2, The second protective layer 226 is overlapped with the second electrodes 256a and 256b of the photosensitive pixels P1 and P2. The first contact hole 264a and the second contact hole 264 are formed in the second passivation layer 226 where the bias line VL overlaps with the second electrodes 256a and 256b of the light sensing pixels P1 and P2 And the bias line VL is electrically connected to the second electrodes 256a and 256b of the photosensitive pixels P1 and P2.

In other words, the adjacent photo-sensing pixels P1 and P2 share one bias line VL and are connected to the PIN diodes 254a and 254b of the two adjacent photo-sensing pixels P1 and P2 via a bias line VL A bias voltage or a reverse bias voltage is simultaneously applied.

At this time, the bias line VL may be formed of a metal having good conductivity such as Cr, Mo, Ta, Cu, Ti, Al and alloys thereof.

A third passivation layer 227 is disposed on the second passivation layer 226 on which the bias line VL is disposed and a scintillator layer 270 is disposed thereon.

The third passivation layer 227 may be formed of an organic insulating material such as photo-acryl or an inorganic insulating material such as SiOx or SiNx. The third passivation layer 227 may be formed of a plurality of layers including an organic insulating layer / an inorganic insulating layer, an inorganic insulating layer / an organic insulating layer / an inorganic insulating layer.

The scintillator layer 270 converts the X-ray transmitted through the object into visible light. The scintillator layer 270 may be formed of a halogen compound such as cesium iodide (CsI) doped with thallium (Tl) or sodium (Na) or an oxide compound such as gadolinium or sulfur oxides .

The scintillator layer 270 may be formed in a film form and attached directly to the substrate 210, or may be formed by directly laminating a scintillator material on the substrate 210.

As described above, in the digital X-ray detecting apparatus according to the first embodiment of the present invention, the two light sensing pixel columns share one bias line, thereby improving the aperture ratio of the photo-sensing pixels and improving the fill factor of the digital X- This is explained in more detail as follows.

FIG. 5 is a diagram showing a digital X-ray detecting device in which bias lines are formed in each of photo-sensing pixel columns.

As shown in FIG. 5, in the digital X-ray detector of this structure, one bias line (VL) is provided in one photo-sensing pixel column to apply a bias voltage or a reverse bias voltage to the PIN diode 254, respectively. At this time, the bias line VL is disposed across the middle region of the photo-sensing pixel P in parallel with the data line DL. Accordingly, the aperture ratio of the photodetector pixel P is lowered by the bias line VL. The amount of light radiated from the scintillator layer to the PIN diode 254 is reduced due to the lowering of the aperture ratio. Therefore, in the digital x-ray detecting apparatus having the structure shown in Fig. 5, there is a problem that the fill factor is reduced due to the decrease in the amount of light and the performance of the digital x-ray detecting apparatus is deteriorated.

3 and 4, since the bias line VL is arranged in the region between the photodetecting pixels P1 and P1 adjacent to each other, the bias voltage VL is applied to the PN diode 254a, and 254b can be minimized and the aperture ratio of the photo-sensing pixels P1 and P2 can be prevented from decreasing. In addition, in the present invention, since the two light sensing pixels P1 and P1 share one bias line VL, the reduction of the aperture ratio of the light sensing pixels P1 and P2 can be minimized.

In the digital X-ray detecting apparatus of the structure shown in FIG. 5, the factor causing the aperture ratio drop in one photodetector pixel P corresponds to the width d1 of the bias line VL. However, Since the bias line VL is disposed in the area between the adjacent PN diodes 254a and 254b, the distance d1 between the bias line VL and the adjacent PN diodes 254a and 254b (I.e., d1-a). Since the two neighboring photodetecting pixels P1 and P1 share one bias line VL, the factor of lowering the aperture ratio due to the bias line VL in one photodetector pixel is (d1-a) / 2 .

Therefore, compared with the digital X-ray detecting apparatus having the structure shown in FIG. 5, the aperture ratio degradation due to the bias line VL in the digital X-ray detecting apparatus according to the present invention is minimized, and as a result, the fill factor of the digital X- .

6 is a plan view showing a digital X-ray detecting apparatus according to a second embodiment of the present invention. Since the structure of this embodiment is the same as the structure of the first embodiment except for the bias line VL, description of the same structure will be omitted and only other structures will be described in detail.

6, in the digital X-ray detecting apparatus of this embodiment, a bias line VL is arranged in an area between two adjacent photosensitive pixels P1 and P2, and two photosensitive pixels P1 and P2 A bias voltage or a reverse bias voltage is applied to the second electrodes 356a and 356b of the photoconductors PC1 and PC2, respectively.

Since the width d2 of the bias line VL is set to be smaller than the interval between the adjacent two photo-sensing pixels P1 and P2, the bias line VL is set between the photo- The bias line VL does not overlap with the second electrodes 356a and 356b of the photoconductors PC1 and PC2. Therefore, unlike the first embodiment, in the digital X-ray detector of this embodiment, the first contact hole and the second contact hole are formed in the region where the bias line VL and the photoconductors PC1 and PC2 overlap with each other, (VL) can not be connected to the second electrodes 356a and 356b.

In the digital X-ray detecting apparatus of this embodiment, the first connection pattern 163a and the second connection pattern 163b are provided in the bias line VL and extend to the adjacent photo-sensing pixels P1 and P2, respectively. In other words, in the digital X-ray detecting apparatus of this embodiment, the bias line VL is not overlapped with the photoconductors PC1 and PC2, but the connecting patterns 163a and 163b are provided with separate connecting patterns 163a and 163b, To the photoconductors PC1 and PC2.

A first contact hole 363a and a second contact hole 363b are formed in the photo sensing pixels P1 and P2 in the regions where the connection patterns 163a and 163b and the photoconductors PC1 and PC2 overlap, The bias line VL is connected to the second electrodes 356a and 356b of the adjacent photodetection pixels P1 and P2 via the connection patterns 163a and 163b and the bias voltage VL is applied to the PIN diodes 354a and 354b, Or a reverse bias voltage.

As described above, in the digital X-ray detecting apparatus of this embodiment, the bias line VL is disposed in the region between the photo-sensing pixels P1 and P2 and does not overlap with the photoconductors PC1 and PC2 of the photo-sensing pixels P1 and P2 Since only the connection patterns 163a and 163b overlap with the photoconductors PC1 and PC2 of the photodetecting pixels P1 and P2 in the region where the photoconductors PC1 and PC2 are covered The aperture ratio can be further reduced, and as a result, the fill factor of the digital x-ray detector can be further improved.

5, the fill factor of the digital X-ray detecting apparatus is about 60.26%, whereas the digital X-ray detecting apparatus according to the first and second embodiments of the present invention has a fill factor of about 64.40-65.50. Therefore, the fill factor of the digital X-ray detecting apparatus according to the present invention is improved by about 4.24 to 5.24% as compared with the digital X-ray detecting apparatus having the structure shown in FIG.

7A to 7D are views showing a method of manufacturing a digital X-ray detecting apparatus according to the present invention. The digital X-ray detecting device manufactured by this process is the digital X-ray detecting device of the first embodiment, but the digital X-ray detecting device according to the second embodiment is also manufactured by the same process.

First, as shown in FIG. 7A, an inorganic insulating material is laminated on a transparent substrate 210 such as glass or plastic by CVD (Chemical Vapor Deposition) to form a buffer layer 221 on the substrate 210.

Then, oxide semiconductors such as IGZO, TiO ₂ , ZnO, WO ₃ , and SnO ₂ are stacked on the buffer layer 221 by a CVD method and etched to form semiconductor layers 112 a and 112 b. Thereafter, an inorganic insulating material such as SiOx or SiNx is deposited on the substrate 210 on which the semiconductor layers 112a and 112b are formed by a CVD method and etched to form the gate insulating layer 222. Next, a metal such as Cr, Mo, Ta, Cu, Ti, or Al or an alloy thereof is deposited on the substrate 210 including the gate insulating layer 222 by a sputtering method, Gate electrodes 211a and 211b are formed on the layer 222. [ At this time, the gate electrodes 211a and 211b may be formed as a plurality of layers by stacking and etching the metal or the alloy with a plurality of layers.

In the above description, the gate insulating layer 222 and the gate electrodes 211a and 211b are formed by forming the gate insulating layer 222 with the width set by etching and forming the gate electrodes 211a and 211b thereon. However, in the present invention, the gate insulating layer 222 and the gate electrodes 211a and 211b may be formed by a single process. That is, in the present invention, after the insulating layer and the metal layer are continuously stacked, the metal layer is etched by wet etching to form the gate electrodes 211a and 211b, The gate insulating layer 221 may be formed by dry etching the insulating layer.

Then, an inorganic material such as SiOx or SiNx is deposited over the entire surface of the substrate 210 and then etched to form an interlayer insulating layer 223 in which the first contact hole 223a and the second contact hole 223b are formed.

7B, a metal such as Cr, Mo, Ta, Cu, Ti, Al, or Al alloy or an alloy thereof is deposited and etched on the entire surface of the substrate 210 to form the interlayer insulating layer 223, The source electrodes 214a and 214b and the drain electrodes 215a and 215b which are formed on the first and second contact holes 223a and 223b and are in contact with the source and drain regions of the semiconductor layers 212a and 212b, 215b.

Thereafter, an organic insulating material and / or an inorganic insulating material is stacked and etched on the entire surface of the substrate 210 to form a first passivation layer 225 having a third contact hole 225a exposed to the outside of the source electrode 214 ).

Then, as shown in FIG. 7C, a metal such as MoTi or a transparent metal oxide such as ITO or IZO is deposited and etched to form a source electrode 214a through the third contact hole 225a on the first passivation layer 225, The first electrodes 252a and 252b are electrically connected to the electrodes 214a and 214b.

Then, a semiconductor material doped with an N-type impurity, an intrinsic semiconductor material, a semiconductor material doped with a P-type impurity, and a transparent conductive material such as ITO and IZO are stacked and etched on the first electrodes 252a and 252b, PIN diodes 254a and 254b and second electrodes 256a and 256b are formed on the first electrodes 252a and 252b. As the semiconductor material, amorphous silicon (a-Si), HgI ₂ , CdTe, PbO, PbI ₂ , BiI ₃ , GaAs, Ge and the like can be used.

Further, semiconductor materials such as amorphous silicon (a-Si), HgI ₂ , CdTe, PbO, PbI ₂ , BiI ₃ , GaAs, and Ge are stacked and doped with N-type impurities, And the PIN diodes 254a and 254b may be formed by doping the P-type impurity into the upper region of the layer.

Thereafter, an organic insulating material, an organic insulating material / inorganic insulating material or an inorganic insulating material / organic insulating material / inorganic insulating material is stacked on the substrate 210 on which the PIN diodes 254a and 254b are formed, The second passivation layer 226 is formed and the second passivation layer 226 is etched to form the fourth contact holes 264a and 264b. A bias line VL is formed on the second passivation layer 226 by depositing and etching a metal such as Cr, Mo, Ta, Cu, Ti, or Al on the second passivation layer 226 or an alloy thereof. do. At this time, the bias line VL is electrically connected to the second electrodes 256a and 256b of the adjacent photo-sensing pixels P1 and P2 via the fourth contact holes 264a and 264b.

Then, an organic insulating material such as photo-acryl and / or an inorganic insulating material such as SiOx or SiNx is stacked on the second protective layer 226 on which the second electrodes 256a and 256b are formed to form an organic insulating layer, A third protective layer 227 made of an insulating layer or an inorganic insulating layer / an organic insulating layer / an inorganic insulating layer is formed.

Subsequently, a halogen compound such as cesium iodide (CsI) doped with thallium (Tl) or sodium (Na) or an oxide compound such as gadolinium or sulfur oxide (GOS) is formed on the third passivation layer 227 And a silylate layer 270 is formed by directly laminating a halogen compound or an oxide-based compound to complete a digital x-ray detector.

As described above, according to the present invention, since the bias lines are disposed in the region between adjacent photo-sensing pixels, the area of the PN diode overlapping with the bias line can be minimized, thereby preventing the aperture ratio of the photo- . Therefore, it becomes possible to improve the fill factor of the digital X-ray detecting device.

Further, in the present invention, since the semiconductor layer of the thin film transistor is formed of the oxide semiconductor material, the area of the thin film transistor can be reduced, so that the aperture ratio of the photo-sensing pixel can be improved. As a result, the fill factor of the digital X-ray detector can be further improved.

In the above description, the digital X-ray detecting apparatus of the present invention is limited to the specific structure, but the present invention is not limited to this specific structure. The structure of the above-described digital X-ray detecting device is illustrated for convenience of explanation and is not intended to limit the present invention. The most important feature of the present invention is that the bias line is shared by two adjacent photo-sensing pixels to improve the fill factor due to the improvement of the aperture ratio of the photo-sensing pixels. Therefore, The present invention can be applied to the above-described embodiments.

GL: gate line DL: data line
VL: bias line 211a, 211b: gate electrode
212a, 212b: semiconductor layers 213a, 213b: source electrode
214a, 214b: drain electrode 221: buffer layer
223: interlayer insulating layer 252a, 252b: first electrode
254a and 254b: PIN diodes 256a and 256b:
270: Scintillator layer

Claims (9)

A substrate comprising a plurality of photo-sensing pixels defined by gate lines and data lines;
A thin film transistor disposed in each of the photo-sensing pixels;
A photoconductor disposed in the photo-sensing pixel and converting light into an electrical signal, the photo-conductor comprising a first electrode and a second electrode, and a PIN diode disposed between the first electrode and the second electrode; And
And a bias line disposed on the photoconductor,
Wherein the bias line is disposed in an area between adjacent photo-sensing pixels. The thin film transistor according to claim 1,
An oxide semiconductor layer;
A gate insulating layer disposed on the semiconductor layer;
A gate electrode disposed on the gate insulating layer;
The semiconductor layer and the gate electrode as an interlayer insulating layer; And
And a source electrode and a drain electrode which are in contact with the semiconductor layer through contact holes formed in the interlayer insulating layer. 2. The digital X-ray detecting apparatus according to claim 1, wherein the bias line is electrically connected to a second electrode of two adjacent photo-sensing pixels. The organic light emitting display according to claim 3, wherein the bias line is a digital X-ray detection circuit which is electrically connected to a second electrode of two adjacent photo-sensing pixels through contact holes provided in overlapping regions, Device. 4. The semiconductor device according to claim 3, further comprising a connection pattern extending from each of the bias lines to each of adjacent photo-sensing pixels, wherein the bias line is connected to two adjacent photo-sensing pixels through contact holes provided below the connection pattern, Is electrically connected to the second electrode of the digital X-ray detector. The digital X-ray detector according to claim 1, wherein the PIN diode comprises a P-type semiconductor layer, an intrinsic semiconductor layer, and an N-type semiconductor layer. The method of claim 6, wherein the semiconductor layer of the PIN diode is a digital X-ray detector consisting of a material selected from amorphous silicon, HgI _2, CdTe, PbO, PbI _2, BiI _3, GaAs, a group consisting of Ge. The digital X-ray detecting apparatus according to claim 1, further comprising a buffer layer stacked on the substrate and having a semiconductor layer on an upper surface thereof. The digital x-ray detector according to claim 1, further comprising a scintillator layer disposed on the photoconductor.

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