WO2014139222A1

WO2014139222A1 - Radio frequency detector and manufacturing method thereof

Info

Publication number: WO2014139222A1
Application number: PCT/CN2013/076795
Authority: WO
Inventors: 田宗民; 阎长江; 谢振宇
Original assignee: 北京京东方光电科技有限公司
Priority date: 2013-03-12
Filing date: 2013-06-05
Publication date: 2014-09-18
Also published as: CN103165635A; CN103165635B

Abstract

A radio frequency detector and a manufacturing method thereof. A gate layer (2) and an insulating layer (3) are successively formed on a substrate (1), and a photodiode (15) and a source/drain layer (6) are formed on the substrate (1) with the formed insulating layer (3); a drain (62) of the source/drain layer (6) is connected to the photodiode (15); an active layer (4) is formed on the source/drain layer (6), and the active layer (4) contacts the insulating layer (3); a first passivation layer (10) is formed on the active layer (4) and the source/drain layer (6), and a through hole (30) is provided on the first passivation layer (10); a conductive thin film layer (11) is formed on the photodiode (15), on the first passivation layer (10), and in the through hole (30).

Description

Ray detector and manufacturing method thereof

Embodiments of the present invention relate to a radiation detector and a method of fabricating the same. Background technique

A functional device that performs photoelectric conversion of image information is called a photoelectric image detector (or photoelectric image sensor). The flat-type ray detector is a photoelectric image detector and is commonly used in the medical field. For example, a flat-type ray detector detects X-rays passing through a human body and displays the intensity distribution of X-rays in different grayscale forms on the display, so that the results of human X-ray detection can be visually observed.

1A and 1B are schematic views showing the structure of a radiation detector of the prior art. The ray detector includes an array of pixels, each of which includes a Thin Film Transistor (TFT) and a photodiode. The TFT generally includes a gate, a source and a drain, and has a switching function to control transmission of an electrical signal between the source and the drain; the photodiode includes a P-type semiconductor layer, a stack of the intrinsic semiconductor layer and the N-type semiconductor layer ( PIN knot). The working principle of the above-mentioned radiation detector is: when X-ray (X-Ray) light is irradiated onto the scintillation layer of the radiation detector, the scintillation layer converts the X-ray into visible light, and the visible light is irradiated. Go to the photo diode. When the TFT is in an active state, an on-voltage is applied on the gate line to turn on the source and drain, and the output of the data line of the liquid crystal display driving circuit is controlled according to the output signal of the photodiode; at this time, the photodiode is reversed under the action of the TFT. At the operating voltage, when the photodiode receives the visible light obtained by the above conversion, the visible light signal can be converted into a corresponding electrical signal output to the TFT, and the TFT outputs a signal to control the driving circuit of the liquid crystal display. In the driving circuit of the liquid crystal display, since different electric signals in different pixels form different electric fields, thereby causing different twisting degrees of liquid crystal molecules, the backlight of the liquid crystal display penetrates liquid crystal molecules with different twist degrees in each pixel. Different pictures are formed, and X-rays are finally converted into image information for display.

The radiation detector is disposed on a glass substrate, and the photosensitive detector is formed by a photodiode connected by a bottom electrode and a drain of the TFT, thereby causing a large coupling capacitance of the radiation detector, thereby causing low sensitivity of the radiation detector and Power consumption is large. The above-described radiation detector is usually patterned using a mask, and the steps are as follows.

Step 200: A gate layer 2 is formed on the glass substrate 1 by a patterning process.

Step 210: sequentially forming an insulating layer 3, an a-Si layer 4, and an N+a-Si layer 5 on a glass substrate 1 on which the gate layer 2 is formed by a patterning process, and patterning the a-Si layers 4 and N The +a-Si layer 5 is patterned.

Step 220: Form a source/drain layer 6 on the N+a-Si layer 5, and form a source and a drain after patterning. Step 230: Forming a first passivation layer 10 on the source, drain, and a-Si layers 4, and patterning the first passivation layer 10 by a patterning process.

Step 240: forming a photodiode on the drain, the photodiode being composed of a P-type semiconductor layer 7, an intrinsic semiconductor layer 8, and an N-type semiconductor layer 9;

Step 250: Form a conductive thin film layer 11 on the photodiode, wherein the photodiode needs to be connected to the drain through the electrode at the bottom thereof.

Step 260: forming a second passivation layer 12 on the conductive film layer 11, the first passivation layer 10, and the glass substrate 1, and opening a first via hole on the second passivation layer 12 adjacent to the conductive film layer 11. And opening a second via hole at a position where the first passivation layer 10 is adjacent to the source.

Step 270: forming a first electrode 13 on the second passivation layer 12, a photodiode, and forming a second electrode 13" on the second passivation layer 12 and the source/drain layer 6 and patterning by a patterning process.

The first electrode 13 and the second electrode 13" constitute a conductive thin film layer 13. In the above-described radiation detector, the first electrode 13 is connected to the photodiode for outputting an operating voltage to the photodiode and receiving an electrical signal output by the photodiode. The second electrode 13" is for controlling the liquid crystal display driving circuit for image display.

Step 280: Forming a third passivation layer 14 on the conductive thin film layer 13 and the second passivation layer 12, and patterning the third passivation layer 14 by a patterning process.

The third passivation layer 14 is used to protect the radiation detector.

It can be seen from the above that the current photodetector needs to adopt 9 mask processes, which has the problems of complicated manufacturing process, long production cycle, low production efficiency, low sensitivity, and large power consumption. Summary of the invention

The production process of the radiation detector existing in the prior art is complicated, the production cycle is long, and the sensitivity is The present invention provides a radiation detector and a method of fabricating the same. An aspect of the invention provides a radiation detector comprising: a substrate; a gate layer formed on the substrate; an insulating layer formed on the gate layer; formed on a substrate on which the insulating layer is formed a photodiode; a source/drain layer formed on the substrate on which the insulating layer is formed, a drain of the source and drain layers is connected to the photodiode; and an active source formed on the source and drain layers a layer, the active layer is connected to the source and drain layers; a first passivation layer formed on the active layer and on the source and drain layers, and opened on the first passivation layer a hole; a conductive film layer formed on the photodiode, on the first passivation layer, and in the via.

Another aspect of the present invention provides a method of fabricating a radiation detector, comprising: forming a gate layer on a substrate; forming an insulating layer on the substrate on which the gate layer is formed, and forming the insulating layer Forming a photodiode on the substrate; forming a source/drain layer on the substrate on which the insulating layer is formed; electrically connecting the drain of the source and drain layers to the photodiode; forming on the source and drain layers a source layer, the active layer is connected to the insulating layer; a first passivation layer is formed on the active layer and the source and drain layers, and a via is formed in the first passivation layer And forming a conductive thin film layer on the photodiode, on the source and drain layers, and in the via. DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly described below. It is obvious that the drawings in the following description relate only to some embodiments of the present invention, rather than to the present invention. limit.

1A is a schematic structural view of an array substrate of a conventional TFT flat panel X-ray sensor, and FIG. 1B is a schematic structural view of a conventional radiation detector;

2A is a schematic structural view of an X-ray detector according to an embodiment of the present invention, and FIG. 2B is an equivalent circuit diagram of an X-ray sensor according to an embodiment of the present invention;

3-8 are schematic diagrams 1 to 6 of a manufacturing process of a radiation detector according to an embodiment of the present invention. detailed description

The technical solutions of the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings. It is apparent that the described embodiments are part of the embodiments of the invention, rather than all of the embodiments. Based on the description All other embodiments of the present invention, which are obtained by those skilled in the art without the need for creative labor, are within the scope of the present invention.

Unless otherwise defined, technical terms or scientific terms used herein shall be of the ordinary meaning understood by those of ordinary skill in the art to which the invention pertains. The terms "first", "second" and similar terms used in the specification and claims of the invention are not intended to indicate any order, quantity or importance, but are merely used to distinguish different components. Similarly, the words "a", "an" or "the" do not mean a quantity limitation, but rather mean that there is at least one. The words "including" or "comprising", etc., are intended to mean that "a" or "comprising" or "an" Component or object. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "Down", "Left", "Right", etc. are only used to indicate the relative positional relationship. When the absolute position of the object to be described is changed, the relative positional relationship may also change accordingly.

In the embodiment of the present invention, the ray detector may be a bottom-gate type ray detector or a top-gate type ray detector. Hereinafter, a bottom-gate type ray detector is taken as an example, and a preferred embodiment of the present invention is described in detail with reference to the accompanying drawings. Description.

2A is a schematic structural view of a radiation detector according to an embodiment of the present invention. The ray detector comprises a pixel array, and the structure of each pixel unit comprises a substrate 1, a gate layer 2, a common electrode 2, an insulating layer 3, an active layer 4, a source/drain layer 6, and a first blunt as shown. The chemical layer 10, the conductive thin film layer 11, the second passivation layer 12, and the photodiode 15 composed of a laminate of the P-type semiconductor layer 7, the intrinsic semiconductor layer 8, and the N-type semiconductor layer 9.

2B is an equivalent circuit diagram of an X-ray sensor of each pixel. C _se is an equivalent circuit of a photodiode for inducing X-rays to generate photoelectric signals; TFT is a switching element, and receiving gate line control; an equivalent circuit of the capacitor, a gate electrode of the TFT is connected to a gate electrode scan line of the pixel unit, The source of the TFT is connected to the data line of the pixel unit.

For example, the substrate 1 may be a glass substrate, a plastic substrate or the like; a gate layer 2 and a common electrode 2 are formed on the substrate 1; and an insulating layer 3 is overlaid on the substrate 1 on which the gate layer 2 and the common electrode 2 are formed. The photodiode 15 and the source and drain layers 6 are formed on the insulating layer 3, and the source and drain layers 6 include a source 61 and a drain 62 which are spaced apart from each other; and an active layer 4 is formed on the source and drain layers 6 and Insulation 3 a first passivation layer 10 is formed on the active layer 4 and the source/drain layer 6; a via 30 is formed in the first passivation layer 10 adjacent to the source 61; and the conductive thin film layer 11 is Formed on the photodiode 15, the source/drain layer 6, and the first passivation layer 10; the conductive thin film layer 11 includes a first electrode 11, and a second electrode 11", the first electrode 11 is formed on the photodiode 15 and On a passivation layer 10, a second electrode 11" is formed in the first passivation layer 10 and the via 30. The first electrode 11, and the second electrode 11" are discontinuously disposed. The second electrode 11" is electrically connected to the source 61 of the thin film transistor for outputting the generated electrical signal. The first electrode 11 is electrically connected to the N-type semiconductor layer 9 as a reverse bias voltage negative electrode. The common electrode 2 can also reflect part of the light transmitted through the PIN junction, thereby improving the sensitivity of detection.

Further, the radiation detecting device may further include a second passivation layer 12 formed on the electroconductive thin film layer 11 and in contact with the first passivation layer 10 through a discontinuous portion on the electroconductive thin film layer 11.

The insulating layer 3 may be a silicon nitride layer or a silicon oxide layer. Preferably, a silicon nitride layer is used as the insulating layer 3; the first passivation layer 10 and the second passivation layer 12 may each be a silicon nitride layer or The silicon oxide layer is an organic insulating layer such as a resin.

The photodiode 15 described above includes a P-type semiconductor layer 7, an intrinsic semiconductor layer 8, and an N-type semiconductor layer 9. The above semiconductor layer may be an amorphous silicon layer or a split layer. The P-type semiconductor layer 7 is on the insulating layer 3, the intrinsic semiconductor layer 8 is on the P-type semiconductor layer 7, and the N-type semiconductor layer 9 is on the intrinsic semiconductor layer 8. Referring to FIG. 2A, the photodiode 15 does not need to be connected to the drain 62 through another bottom electrode, but can be directly connected to the drain 62 in the source/drain layer 6, thereby reducing the photodiode 15 and the drain 62. The coupling capacitance between the two increases the sensitivity of the radiation detector while reducing the power consumption of the radiation detector.

When the thin film transistor is in an active state, the gate line applies an on voltage to cause the source 61 and the drain 62 to be turned on by the active layer 4 that becomes conductive, and the output of the data line of the liquid crystal display driving circuit is controlled according to the output signal of the photodiode 15. At this time, the photodiode 15 is under the reverse operating voltage under the action of the thin film transistor. When the photodiode receives the visible light obtained by the X-ray conversion, the visible light signal can be converted into a corresponding electrical signal output to the thin film transistor. The thin film transistor controls a driving circuit such as a liquid crystal display. In the driving circuit, since different electric signals cause different electric fields, thereby causing different twisting degrees of liquid crystal molecules, the backlight of the liquid crystal display penetrates liquid crystal molecules with different twisting degrees, and different images can be formed, and the incident can be made. X-ray conversion is performed for image information. Based on the embodiment of the invention illustrated in Figures 2A and 2B, the detailed steps of fabricating the radiation detector can be as follows.

Step 400: Forming a gate layer 2 on the substrate 1.

See Figure 3, using! In a 3⁄4 process (e.g., a sputtering process), a conductive film layer is deposited on the substrate 1, and a pattern including the gate layer 2 is formed on the conductive film layer by a patterning process. For example, a photoresist layer is coated, the photoresist layer on the substrate 1 is exposed by a mask process, and then the exposed photoresist layer is developed, and then the conductive film layer is deposited by wet etching. The substrate 1 is etched, and finally the photoresist layer is peeled off to form the gate layer 2 and the common electrode 2 on the substrate 1.

In the embodiment of the present invention, the above-mentioned process may be a sputtering process or a plasma enhanced chemical vapor deposition process (PECVD) process. The conductive film layer may be a metal thin film layer or a metal oxide thin film layer, for example, the conductive film layer is a molybdenum layer.

Step 410: An insulating layer 3 is formed on the substrate 1 on which the gate layer 2 and the common electrode 2 are formed, and a photodiode 15 is formed on the substrate 1 on which the insulating layer 3 is formed.

Referring to FIG. 4, in the embodiment of the present invention, the process of forming the insulating layer 3 and the photodiode 15 is as follows: 3⁄4 process, depositing an insulating layer 3 on the substrate 1 on which the gate layer 2 and the common electrode 2 are formed, and sequentially depositing a P-type semiconductor layer 7 on the insulating layer 3 above the common electrode 2, the intrinsic semiconductor Layer 8 and N-type semiconductor layer 9 are used to obtain a PIN junction. The laminate of the above semiconductor layers is patterned by a patterning process to obtain a photodiode 15; for example, the above plating process is a PECVD process.

The insulating layer 3 may be a silicon nitride layer or a silicon oxide layer, and preferably a silicon nitride layer is used as the insulating layer 3.

Step 420: Forming the source and drain layers 6 on the substrate 1 on which the insulating layer 3 is formed.

Referring to FIG. 5, in the embodiment of the present invention, the process of forming the source/drain layer 6 is as follows: a conductive film layer is formed on the insulating layer 3 on which the gate layer 2 is formed, and a conductive film layer is formed on the conductive film layer. The patterning process forms a pattern including the source and drain layers 6. The source drain layer 6 includes source electrodes 61 and 62 spaced apart from each other.

The P-type semiconductor layer 7 of the photodiode 15 is directly connected to the drain 62 of the source/drain layer 6, and the photodiode 15 is not connected to the drain 62 of the source/drain layer 6 through the bottom electrode of the photodiode 15, thereby reducing The coupling capacitance between the photodiode 15 and the drain improves the sensitivity of the radiation detector while reducing the power consumption of the radiation detector. Step 430: Forming the active layer 4 on the source and drain layers 6.

Referring to FIG. 6, in the embodiment of the present invention, the process of forming the active layer 4 is, for example, forming a oxide layer on the source/drain layer 6 by using a plating process, and forming a pattern by using a patterning process on the oxide layer. The pattern of layer 4. That is, the active layer 4 is formed using an oxide semiconductor layer. The active layer 4 is located above the gate 2.

For example, the above oxide layer is an indium gallium oxide layer; the above process is a sputtering process. Step 440: forming a first passivation layer 10 on the active layer 4 and the source/drain layer 6, and opening a via hole 30 at a position adjacent to the source in the first passivation layer 10.

Referring to FIG. 7, in the embodiment of the present invention, the process of forming the first passivation layer 10 is, for example, a film of the first passivation layer 10 formed on the active layer 4 and the source and drain layers 6 by a plating process. The via hole 30 is formed by patterning the first passivation layer 10.

For example, the above plating process is a sputtering process.

Step 450: Forming a conductive thin film layer 11 on the photodiode 15 and the first passivation layer 10 and in the via 30.

For example, the conductive thin film layer 11 includes the first electrode 11 and the second electrode is 11". The first electrode 11 is formed on the photodiode 15 and the first passivation layer 10, and the first passivation layer 10 and the via hole are formed. A second electrode 11" is formed in 30.

Referring to FIG. 8, in the embodiment of the present invention, the process of forming the conductive thin film layer 11 is as follows: In the 3⁄4 process, a conductive film layer is formed in the photodiode 15, the first passivation layer 10, and the via hole, and a pattern including the conductive thin film layer 11 is formed by patterning the conductive film layer. For example, the first passivation layer 10 is a silicon nitride or silicon oxide layer.

For example, the above plating process is a sputtering process.

Step 460: Forming a second passivation layer 12 on the electroconductive thin film layer 11.

In the embodiment of the present invention, a second passivation layer film is formed on the conductive thin film layer 11 by using a process, and a pattern including the second passivation layer 12 is formed by patterning the second passivation layer film. The second passivation layer 12 is, for example, a silicon nitride layer or a silicon oxide layer.

For example, the above 3⁄4 process is a PECVD process.

The above embodiment includes the common electrode 2 to form a storage capacitor; in other embodiments of the present invention, the common electrode may not be formed, i.e., the common electrode is optional.

In summary, in the embodiment of the present invention, a gate layer and an insulating layer are sequentially formed on a substrate, and Forming a photodiode and a source/drain layer on the substrate on which the insulating layer is formed; a drain of the source and drain layers is connected to the photodiode; and an active layer is formed on the source and drain layers, the active layer The insulating layer is in contact with each other; a first passivation layer is formed on the active layer and the source and drain layers, and a via hole is formed at a position adjacent to the source of the first passivation layer 10; on the photodiode And a first passivation layer, and a conductive film layer is formed in the via hole, and a second passivation layer is formed on the conductive film layer. Compared with the prior art, the technical solution of the invention reduces the number of masks, effectively shortens the production cycle, improves the production efficiency, reduces the manufacturing cost, and reduces the photodiode and the drain due to the direct connection of the photodiode and the drain. The coupling capacitance between the two increases the sensitivity of the radiation detector while reducing the power consumption of the radiation detector.

The above is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims.

Claims

claims

1. A radiation detector, including:

substrate;

a gate layer formed on the substrate;

an insulating layer formed on the gate layer;

A photodiode formed on a substrate on which the insulating layer is formed;

a source-drain layer formed on the substrate on which the insulating layer is formed, the drain of the source-drain layer being connected to the photodiode;

an active layer formed on the source and drain layer, the active layer connecting the source and drain layer; a first passivation layer formed on the active layer and the source and drain layer, and opening via holes on the first passivation layer;

A conductive film layer is formed on the photodiode, on the first passivation layer and in the via hole.

2. The radiation detector of claim 1, wherein the photodiode includes a P-type semiconductor layer formed on the insulating layer, and an intrinsic semiconductor layer formed on the P-type semiconductor layer,

3. The radiation detector according to claim 2, wherein the P-type semiconductor layer of the photodiode is connected to the drain of the source-drain layer.

4. The radiation detector according to any one of claims 1 to 3, further comprising a second passivation layer formed on the conductive film layer.

5. The radiation detector according to any one of claims 1 to 4, further comprising a common electrode formed on the substrate, and the photodiode is formed on the common electrode through the insulating layer.

6. A method for manufacturing a ray detector, including:

forming a gate layer on the substrate;

Forming an insulating layer on the substrate on which the gate layer is formed, and forming a photodiode on the substrate on which the insulating layer is formed;

A source-drain layer is formed on the substrate on which the insulating layer is formed; the drain of the source-drain layer is electrically connected to the photodiode;

An active layer is formed on the source and drain layer, and the active layer is connected to the insulating layer; a first passivation layer is formed on the active layer and the source and drain layer, and The first blunt Open via holes on the chemical layer;

7. The method of claim 6, wherein forming the photodiode on the substrate on which the insulating layer is formed includes:

A P-type semiconductor layer, an intrinsic semiconductor layer and an N-type semiconductor layer are sequentially formed on the substrate on which the insulating layer film is formed. The P-type semiconductor layer, the intrinsic semiconductor layer and the N-type semiconductor layer form the photodiode.

8. The method of claim 6 or 7, wherein forming the source and drain layers on the substrate on which the insulating layer is formed includes:

A conductive film layer is formed on the substrate on which the insulating layer is formed, and a patterning process is used on the conductive film layer to form a pattern including the source and drain layers.

9. The method according to any one of claims 6 to 8, wherein an active layer is formed on the source and drain layers, and the active layer is connected to the insulating layer, including:

An oxide layer is formed on the source and drain layers, and a patterning process is used on the oxide layer to form a pattern including the active layer on the source and drain layers, wherein the active layer and the Insulation connection.

10. The method according to any one of claims 6 to 9, wherein forming a first passivation layer on the active layer and the source and drain layers includes:

A first passivation layer film is formed on the active layer and the source and drain layer, and a patterning process is used on the first passivation layer film to form a pattern including the first passivation layer.

11. The method according to any one of claims 6 to 10, wherein forming a conductive film layer on the photodiode, the first passivation layer and the via hole includes:

A conductive film layer is formed on the photodiode, on the first passivation layer and in the via hole, and a patterning process is used on the conductive film layer to form a pattern including the conductive film layer.

12. The method of claim 11, wherein the first passivation layer is a silicon nitride layer or a silicon oxide layer.

13. The method of any one of claims 6-12, further comprising forming a second passivation layer on the conductive film layer.

14. The method of any one of claims 6 to 13, further comprising forming a common electrode while forming the gate layer on the substrate, and then forming a common electrode through the insulating layer. forming said photodiode,