KR100886973B1 - Digital x-ray detector and method for fabricating it - Google Patents

Abstract

Disclosed is a digital x-ray detector for detecting information stored in a pixel and displaying information by an external integrated circuit, and a method of manufacturing the same. The present invention relates to a digital x-ray detector having a gate wiring and a source / drain intersecting each other on an insulating substrate. And an etch stopper type switching element arranged at an intersection portion of the gate line and the data line, a pixel array unit having a first transparent electrode connected to the switching element and a first transparent electrode connected to the source electrode of the switching element. And a second transparent electrode constituting a part of the capacitor and an additional pixel array part not connected to the source electrode, having the same structure as the pixel array part around the pixel array.

Description

Digital x-ray detector and method for manufacturing the same

1 is a plan view illustrating a pixel structure of a pixel and an additional pixel unit of a pixel array unit in a digital x-ray detector according to the present invention.

2 is a diagram illustrating pixel arrangement and additional pixel arrangement in a digital x-ray detector according to the present invention;

3A to 3B are cross-sectional views illustrating a digital x-ray detector according to a first embodiment of the present invention.

4A to 4B are cross-sectional views illustrating a digital x-ray detector according to a second embodiment of the present invention.

5 is a structural diagram of a digital x-ray detector according to a third embodiment of the present invention.

FIG. 6 is a plan view showing real pixels, dark line pixels and dummy dark lines in a digital x-ray detector according to a third embodiment of the present invention; FIG.

7A is a cross-sectional view illustrating a dark line pixel in a digital x-ray detector according to a third exemplary embodiment of the present invention.

7B is a process cross-sectional view showing real pixels and dummy pixels in a digital x-ray detector according to a third embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital x-ray detector and a manufacturing method thereof, and more particularly, to a digital x-ray detector for displaying information by detecting charge stored in a pixel by an external integrated circuit and a manufacturing method thereof. will be.

The X-ray imaging method using film printing, which is currently used for medical treatment, has to go through the printing process after film shooting, so that the result can be recognized after a certain period of time, and there are many difficulties in storing and preserving the film after shooting. There are disadvantages. Therefore, in order to alleviate these disadvantages, much research has recently been conducted on the fabrication of digital X-ray detectors using thin film transistor arrays.

This method has the advantage of being able to check the result immediately after the X-ray imaging using the thin film transistor and the result of the digital signal, which is easy to store and semi-permanent.

The structure and operation principle of the digital x-ray detector currently being proposed are as follows.

Conventional digital x-ray detectors include capacitors capable of charging charges generated by X-rays on insulating substrates, switching elements for transferring charges charged in capacitors to external lead-out integrated circuits, and charging X-rays in capacitors. It includes a photo-conversion unit for converting to a charge that can be made, a charge collecting electron (CCE) that can collect the charge generated in the photo-conversion unit and a high-voltage direct current device for applying a voltage to move the charge generated in the photo-conversion unit to the capacitor It is configured by.

Among the above components, the thin film transistor existing below by the formation of a guard ring that traps electric charges generated around the pixel portion has a structure that is not connected to the CCE (CCE) electrode. The data line of the portion where the CCE electrode and the thin film transistor are not connected is called a dark line.

The operation of the digital X-ray detector having the above configuration is as follows.

First, electron-hole pairs are formed in the light conversion unit by X-rays. The thus formed electron-hole pairs are separated in each direction by a high voltage direct current device and charges are stored in the capacitor through the CCE. The stored charge drives the thin film transistor and is moved to the integrated circuit unit connected to the end of the data line. The charge transferred to the integrated circuit unit is converted into an image signal to display an X-ray photographing result.

Although only the principle of the digital X-ray detector has been described above, the driving of an image sensor using a thin film transistor has the same principle in that the charge charged in the pixel portion is read out to an external integrated circuit through the thin film transistor. However, only the method of charging the pixel capacitor is changed depending on the purpose of use of the image sensor.

However, in the prior art, information distortion due to external noise (undesired leakage current, charge injection due to scan line pulses) is generated due to the characteristics of sensors detecting charge through data lines.

In addition, according to the related art, since the CCE electrode and the thin film transistor are not connected to each other, when the dark line is opened, the leakage current of the thin film transistor is measured to compensate for the measured amount. There was a problem that occurred.

Accordingly, the present invention has been made to solve the above-mentioned problems, and provides a digital X-ray detector capable of compensating for external noise to prevent information distortion, and detecting a malfunction when the dark line is opened, and a method of manufacturing the same. The purpose is.

The digital x-ray detector of the present invention for achieving the above object is a data wiring having a gate wiring and a source / drain arranged on each other on an insulating substrate, and an etch stopper type switching element arranged at the intersection of the gate wiring and the data wiring And a first transparent electrode for the storage capacitor connected to the switching element, the first transparent electrode having the same structure as the pixel array portion connected to the source electrode of the switching element, and a pixel array portion around the pixel array. And a second transparent electrode constituting part of the capacitor and an additional pixel array part not connected to the source electrode.

The method of manufacturing the X-ray detector of the present invention having the above structure includes the steps of forming a data line having a gate line and a source / drain intersecting with each other on an insulating substrate, and a portion where the gate line and the data line cross each other. Forming an array of etch stopper-type switching elements, and having a first transparent electrode for a storage capacitor connected to the switching element, wherein the first transparent electrode is connected to the source electrode of the switching element and the periphery of the pixel array And an additional pixel array portion having the same structure as that of the pixel array but having a second transparent electrode constituting a part of the capacitor and a source not connected to the pixel array.

It is preferable to form a dielectric layer on the first transparent electrode by using any one of a silicon nitride film, a silicon oxide film, and a silicon oxynitride film or a laminated film thereof.

According to another exemplary embodiment of the present invention, an X-ray detector may include a first transparent electrode for a storage capacitor connected to an optical switching unit and a bias line that receive X-ray light and generate a charge, and a second transparent electrode for a storage capacitor including a pixel electrode. And a switching ring connected to the second transparent electrode, the guard ring collecting charges, and a dark line formed under the guard ring to darken the leakage amount of the thin film transistor in the switching device and correct the amount. It is characterized by.

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

1 is a plan view illustrating a pixel structure of a pixel and an additional pixel unit of a pixel array unit in a digital x-ray detector according to the present invention.

2 is a pixel arrangement and an additional pixel arrangement in the digital x-ray detector according to the present invention.

3A to 3B are cross-sectional views of a pixel array unit cut along line AB of FIG. 3A, and FIG. 3B is an additional pixel array cut along line CD of FIG. 1. Negative process cross section.

In the digital X-ray detector according to the present invention, as shown in FIG. 1, the gate line 10 and the data line 20 are arranged to cross each other on an insulating substrate, and the crossing portion is a pixel array unit, and the gate electrode is provided. The switching element A of the thin film transistor structure including the source / drain electrodes is formed.

The pixel array unit (the right part of FIG. 1 and FIG. 3A) has a capacitor to charge electric charges generated in response to X-rays, and the first transparent electrode 12 constituting a part of the capacitor includes a common electrode 18. The second transparent electrode 16 is connected to the source electrode 30 of the switching element.

In addition, an additional pixel array portion (the left portion of FIG. 1 and FIG. 3B) having a form similar to the pixel structure of the active layer is formed on the outer portion of the active layer of the pixel array portion. In this case, unlike the pixel array unit existing in the active layer, as shown in FIG. 3B, the additional pixel array unit may not be connected to the source electrode 30 of the thin film transistor. Has no structure.

Meanwhile, a material on which an electron-hole pair is formed in response to an X-ray such as Se is formed on the pixel array unit by chemical vapor deposition, thermal vacuum deposition, sputtering, etc., on which the electron-hole formed in Se is separated. There is an electrode (not shown) for applying a high voltage.

Next, when the driving driver is bonded to the gate and the data pad part and sealed, the digital X-ray detector module is completed.

In the method of manufacturing the digital X-ray detector according to the first embodiment of the present invention, as shown in FIGS. 1, 3A, and 3, after the gate wiring 10 is formed on the insulating substrate 1, the substrate 10 is formed on the substrate. The gate insulating film 11, the active layer 20, and the ohmic contact layer 22 are sequentially formed on the substrate.

Next, after forming the first transparent electrode 18 of the storage capacitor, a first opening (not shown) for contact between the gate electrode 10 and the source / drain electrode is formed and the source / drain electrode 30 ( 32 and data wirings 20 are formed.

In this case, the common electrode 14 is formed to be arranged in a direction parallel to the data line 20, and the common electrode 14 is connected to the first transparent electrode 18.

A protective film 13 is then formed on the entire surface of the resulting substrate having a second opening a that exposes the data pad portion and the source electrode 30. In this case, as shown in FIG. 2B, the protective layer on the source electrode is not removed because the dark line part is not connected between the second transparent electrode and the source electrode.

Thereafter, a second transparent electrode 16 connected to the source electrode 30 is formed through the second opening a. In this case, as shown in FIG. 3, the second transparent electrodes 16 on the dark line part are connected to each other and to the signal line outside the pixel. The charges charged in the capacitor of the dark line part are emitted through a signal line connected to the outside of the element rather than being read out through the thin film transistor.

As illustrated in FIG. 2, the dark line unit may be formed on one or both sides of the pixel array unit. The dark line part may be formed of one line or may be formed of several lines.

4 to 4 are cross-sectional views illustrating a digital x-ray detector according to a second embodiment of the present invention.

4A is a cross-sectional view of the pixel array unit cut along the line A-B of FIG. 1, and FIG. 4B is a cross-sectional view of the additional pixel array unit cut along the line C-D of FIG. 1.

The digital x-ray detector according to the second embodiment of the present invention has the same structure as that of the pixel array unit around the pixel array, similarly to the first embodiment of the present invention, and includes a second transparent electrode constituting a part of the capacitor. It has a configuration including an additional pixel array portion that is not connected to the source electrode.

A method of manufacturing a digital x-ray detector according to a second embodiment of the present invention having the above configuration will be described with reference to FIGS. 4A to 4B.

First, after the gate wiring 10 is formed on an insulating substrate 100 such as glass, the gate insulating film 11, the active layer 20, and the ohmic contact layer 22 are sequentially formed.

Next, the source / drain electrodes 30 and 32 and the data line 20 are formed. Then, the first insulating film 40 is formed on the entire surface of the substrate having the above structure, and then the first insulating film of the portion where the electrical passage between the common electrode and the first transparent electrode to be formed in the subsequent process is formed is removed.                     

Thereafter, after forming the first transparent electrode 18 of the storage capacitor, a second insulating film 42 to be the dielectric layer of the capacitor is formed on the entire surface of the substrate including the first transparent electrode 18. At this time, the second insulating film 42 is formed using a single film of any one of a silicon nitride film, a silicon oxide film and a silicon oxynitride film or a stacked film thereof.

Next, the first and second insulating layers 40 and 42 are etched to form openings b for connecting the second transparent electrode and the source electrode to serve as a CCE in a subsequent process. In this case, as illustrated in FIG. 4B, the first and second insulating layer etching processes are not performed in the pixel region of the dark line portion formed outside the active region. As a result, the source electrode 30 of the dark line portion is not connected to the second transparent electrode 16 formed in the subsequent process (see part C of FIG. 2).

Thereafter, a second transparent electrode 16 connected to the source electrode 30 through the opening b is formed in the resultant.

The CCEs present in the dark line portion are connected to each other and to the signal line outside the pixel, and the charges charged in the capacitor of the dark line portion are emitted through the signal line connected to the outside of the pixel without being read out through the thin film transistor.

In the first and second embodiments of the present invention, the digital x-ray detector has been described as an example. However, the application of digital x-ray, which is a basic concept of the present invention, outputs the charge stored in the pixel portion through an data line to an external integrated circuit. It can also be applied to image sensors that display.

5 is a structural diagram of a digital x-ray detector according to a third embodiment of the present invention.                     

6 is a plan view illustrating a real pixel, a dark line pixel, and a dummy dark line in the digital x-ray detector according to the third embodiment of the present invention.

7A is a cross-sectional view illustrating a dark line pixel in the digital X-ray detector according to the third embodiment of the present invention, and FIG. 7B illustrates a real pixel and a dummy pixel in the digital x-ray detector according to the third embodiment of the present invention. The process cross-sectional view shown.

As shown in FIG. 5, the digital X-ray detector according to the third embodiment of the present invention includes a first transparent electrode for a storage capacitor connected to a light conversion unit and a bias line that receives an X-ray light and generates a charge, and a pixel electrode. And a second transparent electrode for the storage capacitor, and a switching element connected to the second transparent electrode, the guard ring collecting charges and a lower portion of the guard ring, which is formed under the guard ring and leads out of the leakage amount of the thin film transistor in the switching element. It comprises a dark line for correcting the amount.

In the manufacturing method of the digital X-ray detector according to the third embodiment of the present invention having the above configuration, as shown in FIG. 5, first, a scan line is partially formed in a scan line for forming a scan line and using the electrode as a thin film transistor. Form a pattern.

Subsequently, an insulating film is formed, and a line for delivering a bias signal and a lead-out line are formed after patterning the bias electrode metal. At this time, the source / drain electrodes 310 and 312 of the thin film transistor are simultaneously formed. Then, the CCE electrode 314 is formed, and the CCE electrode 314 extends to the upper portion of the thin film transistor of the next stage and removes the charge generated by X-ray irradiation on the thin film transistor.

During the above process, pixels formed between the dark line formed at the outer portion and the dummy scan lines formed at the beginning and the end of the scan line are simultaneously formed.

The dummy pixel has the same function as the actual pixel and can be normally checked during the test. If the pixel formed at the end is checked for abnormal operation during the test, it can be seen that an open has occurred in the middle of the dark line.

7A and 7B, reference numeral 300 denotes a substrate, 302 denotes a gate electrode, 304 denotes a gate insulating film, 306 denotes a protective film, and 340 denotes an upper electrode.

As described above, the present invention has a structure similar to the pixel inside the active layer in a portion of the pixel array portion, but by forming a second transparent electrode constituting a portion of the capacitor and the additional pixel array portion where the source is not connected, digital x-ray Signal noise during data line readout, an important factor in driving, can be detected to obtain excellent X-ray imaging results without signal noise.

In addition, the present invention has the advantage that by connecting the CCE electrode of a portion of the pixels connected to the dark line with the thin film transistor, the open test can be prevented to prevent inflow of defects into the final process.

In addition, this invention can be implemented in various changes within the range which does not deviate from the summary.

Claims (4)

Data wiring having a gate wiring and a source / drain intersecting each other on an insulating substrate, An etch stopper type switching element arranged at a portion where the gate line and the data line cross each other; A pixel array unit having a first transparent electrode for a storage capacitor connected to the switching element, wherein the first transparent electrode is connected to a source electrode of the switching element; The X-ray detector having the same structure as the pixel array unit around the pixel array, but including a second transparent electrode constituting a part of the capacitor and an additional pixel array unit not connected to the source electrode. Forming a data line having a gate line and a source / drain intersecting each other on an insulating substrate, Forming an etch stopper type switching element arranged at a portion where the gate line and the data line cross each other; Has a first transparent electrode for the storage capacitor connected to the switching element, the first transparent electrode has the same structure as the pixel array around the pixel array and the pixel array connected to the source electrode of the switching element, And forming a second transparent electrode constituting a part of the capacitor and an additional pixel array portion at which the source is not connected at the same time. The method of manufacturing an x-ray detector according to claim 2, wherein a dielectric layer is formed on the first transparent electrode by using any one of a silicon nitride film, a silicon oxide film, and a silicon oxynitride film or a laminated film thereof. A first transparent electrode for a storage capacitor connected to a light conversion unit and a bias line that receive X-ray light and generate charges; A second transparent electrode for a storage capacitor comprising a pixel electrode, A guard ring having a switching element connected to the second transparent electrode and collecting charges; And a dark line formed below the guard ring and including a dark line to read out the amount of leakage of the thin film transistor and correct the amount of the thin film transistor in the switching element.

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