US-20260126556-A1 - RADIATION DETECTOR

Abstract

The radiation detector includes a GaN detector array including a plurality of GaN detectors tiled to form a desired array structure, a readout element electrically connected to the GaN detectors, and a base circuit board electrically connected to the readout element.

Inventors

• Toru Aoki
• Joung Hun SHIN

Assignees

• BTOZ HOLDINGS CO.,LTD
• Joung Hun SHIN

Dates

Publication Date

20260507

Application Date

20231011

Priority Date

20221130

Claims (5)

1. 1 . A radiation detector comprising: a GaN detector array comprising a plurality of GaN detectors tiled to form a desired array structure; a readout element electrically connected to the GaN detectors; and a base circuit board electrically connected to the readout element.
2. 2 . The radiation detector of claim 1 , wherein the GaN detector comprises an active region including a plurality of pixels for detecting radiation, and a barrier region surrounding the active region, and wherein the barrier region has a size corresponding to one pixel of the GaN detector.
3. 3 . The radiation detector of claim 1 , wherein the GaN detector comprises a GaN substrate, a nitride semiconductor layer formed on the GaN substrate, a lower electrode formed on a lower side of the GaN substrate, and an upper electrode formed on an upper side of the nitride semiconductor layer, and wherein a side surface of the nitride semiconductor layer comprises a slanted surface that is inclined at a predetermined angle with respect to a vertical direction.
4. 4 . The radiation detector of claim 3 , wherein the predetermined angle is a value between 8 degrees and 10 degrees.
5. 5 . The radiation detector of claim 1 , wherein the GaN detector comprises a plurality of pixels for detecting radiation, and wherein each of the plurality of pixels comprises a capacitor for storing charges generated by incident radiation, and a transistor connected to the capacitor and acting as a charge-sensitive amplifier.

Description

TECHNICAL FIELD The present invention relates to a radiation detector that can be used in a radiation imaging device. BACKGROUND ART Conventional radiation detectors include, for example, CdTe or CZT: CdZnTe single crystals as a conversion layer that responds to radiation. Since these single crystals contain cadmium, a hazardous heavy metal, an alternative single crystal is required. Gallium nitride (GaN) single crystals were introduced to replace cadmium-based single crystals, and GaN has a large energy band gap like CdTe, making it easy to implement image acquisition methods such as photon counting, and is thus gaining attention as a radiation detector material. Meanwhile, GaN single crystals are known to have several advantages over CdTe single crystals as a radiation detector material. For example, GaN single crystals have several advantages, such as high resolution and high contrast due to direct conversion, lower energy than CdTe, high sensitivity at about 10 to 30 keV, excellent radiation resistance, stable electrical properties at high temperatures compared to CdTe, high degree of freedom in the manufacturing process, and easy handling due to the hard material properties compared to CdTe. A technology for implementing a radiation detector using GaN with such excellent properties is required. In particular, when tiling individual GaN detectors to configure a detector with a larger area, a method for reducing the size of the dummy area between the active areas is required. In addition, a GaN detector with reduced noise and easy impedance matching is required. PRIOR ART DOCUMENTS European Patent No. EP2764552 (2019 Nov. 13.)U.S. Pat. No. 8,405,037 (2013 May 26.) DETAILED DESCRIPTION OF THE INVENTION Technical Problem The problem to be solved by the present invention is to provide a radiation detector capable of reducing the size of a dummy area between a plurality of tiled GaN detectors and preventing leakage in an edge area. Technical Solution A radiation detector according to an embodiment of the present invention includes: a GaN detector array comprising a plurality of GaN detectors tiled to form a desired array structure; a readout element electrically connected to the GaN detectors; and a base circuit board electrically connected to the readout element. The GaN detector may include an active region including a plurality of pixels for detecting radiation and a barrier region surrounding the active region, and the barrier region may have a size corresponding to one pixel of the GaN detector. The GaN detector may include a GaN substrate, a nitride semiconductor layer formed on the GaN substrate, a lower electrode formed on a lower side of the GaN substrate, and an upper electrode formed on an upper side of the nitride semiconductor layer. A side surface of the nitride semiconductor layer may include a slanted surface that is inclined at a predetermined angle with respect to a vertical direction. The predetermined angle may be a value between 8 degrees and 10 degrees. The GaN detector may include a plurality of pixels for detecting radiation. Each of the plurality of pixels may include a capacitor for storing charges generated by incident radiation, and a transistor connected to the capacitor and acting as a charge-sensitive amplifier. Effect of the Invention According to the present invention, the size of the dummy region between a plurality of tiled GaN detectors can be reduced, and leakage current caused by sparks in the edge region can be effectively prevented. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a radiation detector according to an embodiment of the present invention. FIG. 2 is a drawing schematically showing a cross-sectional structure of a radiation detector according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a GaN detector of a radiation detector according to an embodiment of the present invention. FIG. 4 is a drawing showing an example of an internal circuit structure of a pixel of a GaN detector according to an embodiment of the present invention. EMBODIMENTS FOR CARRYING OUT THE INVENTION Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the described embodiments. In this specification, when a component is mentioned as being above or below another component, it means that it is directly located above or below the other component, or another component may be interposed between them. In addition, the thickness of the component or layer in the drawings may be exaggerated for easy explanation and understanding. It should be understood that parts indicated by the same drawing reference numerals throughout the specification represent the same component. Referring to FIG. 1, a radiation detecto