WO2014185643A1 - Image sensor using photodiode - Google Patents

Image sensor using photodiode Download PDF

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Publication number
WO2014185643A1
WO2014185643A1 PCT/KR2014/003787 KR2014003787W WO2014185643A1 WO 2014185643 A1 WO2014185643 A1 WO 2014185643A1 KR 2014003787 W KR2014003787 W KR 2014003787W WO 2014185643 A1 WO2014185643 A1 WO 2014185643A1
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doped region
type
region
high concentration
image sensor
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PCT/KR2014/003787
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French (fr)
Korean (ko)
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페카 코즈넌야리
허성근
Original Assignee
주식회사 레이언스
주식회사 바텍이우홀딩스
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Publication of WO2014185643A1 publication Critical patent/WO2014185643A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H01L27/14658—X-ray, gamma-ray or corpuscular radiation imagers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
    • H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
    • H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
    • H01L31/103—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the PN homojunction type

Definitions

  • the present invention relates to an image sensor using a photodiode, and more particularly, to an image sensor capable of improving sensitivity while maintaining a fill factor.
  • the digital image sensor includes a pixel arranged in a matrix form and having a photodiode for converting incident light into an electrical signal.
  • the photodiode is designed to have a large area in terms of increasing the fill factor.
  • the junction capacitance is also increased, resulting in a problem that the sensitivity is lowered. This causes not only an increase in X-ray irradiation time but also an increase in image conversion time.
  • the present invention has a problem to provide a way to improve the sensitivity while maintaining the fill factor of the photodiode.
  • the present invention is formed on a substrate, and comprises a first doping region of high concentration n-type or p-type and a second doping region of the same conductivity type as the first doping region of low concentration And a photodiode, wherein the first doped region is configured to surround the second doped region.
  • the photodiode may include a third doped region of a conductive type opposite to the first and second doped regions of low concentration.
  • the photodiode may include a contact region connected to the first doped region and extending to the substrate surface.
  • the present invention provides a low concentration p-type doped region formed in a substrate, a high concentration n-type doped region formed in the low concentration p-type doped region, and a low concentration n-type doped region formed in the high concentration n-type doped region.
  • a photodiode comprising a; A contact region extending from the high concentration n-type doped region to the surface of the substrate, wherein the low concentration n-type doping region and the high concentration n-type doping region have the same depth at substantially the same height in the substrate, and the low concentration
  • the present invention provides an image sensor surrounded by a donut shape by a high concentration of n-type doping regions in a state in which an outer circumferential surface of an n-type doping region has a contact with an inner circumference of a high concentration of n-type doping regions.
  • the contact region may include a contact region that extends from the low concentration p-type doping region to the high concentration n-type doping region.
  • the present invention provides a photoconductive layer comprising a high concentration doped region of a second conductivity type formed in a semiconductor layer of a first conductivity type and a low concentration doped region of a second conductivity type formed in a high concentration doped region of the second conductivity type. And a diode, wherein the heavily doped region of the second conductivity type and the lightly doped region of the second conductivity type have the same depth at substantially the same height in the substrate, and the outer circumferential surface of the low concentration n-type doped region has a high concentration of n.
  • the present invention provides an image sensor that is surrounded by a donut shape by a high concentration of n-type doping regions in contact with an inner circumferential surface of the type doping region.
  • the contact region may include a contact region that extends from the surface of the first conductive semiconductor layer to the heavily doped region of the second conductive semiconductor.
  • a low concentration doped region of the same conductivity type is formed inside a high concentration n-type or p-type doped region of the photodiode. Accordingly, the depletion layer is formed substantially the same as the case where the low concentration doped region is not formed, so that the fill factor reduction can be prevented.
  • the area of the high concentration doped region is reduced by the area occupied by the low concentration doped region.
  • the photodiode capacitance is reduced and the sensitivity can be improved.
  • FIG. 1 is a perspective view schematically showing an X-ray imaging apparatus using an image sensor according to an embodiment of the present invention.
  • FIGS. 2 and 3 are a cross-sectional view and a plan view schematically showing a photodiode structure of an image sensor according to an embodiment of the present invention, respectively.
  • FIG. 1 is a perspective view schematically illustrating an X-ray imaging apparatus using an image sensor according to an embodiment of the present invention
  • FIGS. 2 and 3 schematically illustrate a photodiode structure of an image sensor according to an embodiment of the present invention. Sectional and top view.
  • X-ray imaging apparatuses of various forms and uses may be used.
  • various X-ray imaging apparatuses such as a mammography apparatus or a CT apparatus may be used.
  • the dental X-ray imaging apparatus is taken as an example as an X-ray imaging apparatus for convenience of explanation.
  • the X-ray imaging apparatus 100 may be included.
  • the base 110 the support pillar 120, the lifting member 130, the jaw support member 140, the rotary arm support member 150, the rotation arm 160, the rotation arm driving means 170, the X-ray generator 180, and the image sensor 200 may be included.
  • the base 110 is placed on the ground to support the support pillar 120 on which the above-described components are installed.
  • the support pillar 120 is connected to the base 110 and has a state extending vertically from the base 110.
  • the elevating member 130 is installed on the support pillar 120 to move up and down along the support pillar 120 through a driving means such as a motor. Through this operation, the height of the jaw support member 140 can be adjusted according to the height of the patient who is the subject.
  • Jaw support member 140 is installed on the elevating member 130, it is to support the jaw of the patient.
  • the head of the subject that is, the subject can be located between the X-ray generator 180 and the image sensor 200.
  • the rotary arm supporting member 150 is connected to the upper portion of the elevating member 130 and extends in a direction parallel to the ground.
  • the rotary arm 160 is connected to the lower portion of the rotary arm support member 150.
  • the rotary arm 160 connected as described above may perform a horizontal movement in a direction parallel to the ground or a rotational movement based on a rotation axis perpendicular to the ground by the rotary arm driving means 170.
  • the rotary arm 160 may include a horizontal portion connected to the rotary arm supporting member 150 and a vertical portion bent downward at both ends of the horizontal portion.
  • the X-ray generator 180 corresponds to a configuration of generating X-rays and irradiating them to the subject.
  • the irradiated X-rays are incident to the image sensor 200 through the subject.
  • the image sensor 200 corresponds to a configuration for detecting X-rays passing through the subject and converting the same into an electrical signal.
  • the image sensor 200 may have a rectangular shape in plan, but is not limited thereto.
  • a direct method of directly converting X-rays into an electrical signal or an indirect method of converting X-rays into visible light and then converting visible light into an electrical signal may be used. have.
  • the image sensor 200 is provided with a phosphor (scintillator) for converting the X-rays to visible light.
  • the phosphor may be formed of cesium iodide (CsI), but is not limited thereto.
  • the image sensor 200 may use, for example, a CMOS substrate.
  • pixels are arranged in a matrix in a row direction and a column direction, and each pixel includes a photodiode for converting incident light into an electrical signal.
  • the photodiode according to the embodiment of the present invention is to form a low concentration doping region of the same conductivity type in a high concentration doping region. Accordingly, the sensitivity is improved while maintaining the fill factor, which will be described in more detail.
  • the photodiodes formed in each pixel for example, p-type doped region 221 and n formed on the substrate 211 as a PN contact photodiode Type doped region 222.
  • a silicon substrate may be used as the substrate 211, but is not limited thereto.
  • the p-type doped region 221 may be composed of a lightly doped p ⁇ doped region.
  • the p-type doped region 221 may be formed on the high concentration p + substrate 211 by an epitaxial growth method.
  • the n-type doped region 222 may be formed of a high concentration of n + doped region, and may be formed in the p-type doped region.
  • a contact region 223 extending in a direction perpendicular to the surface of the substrate 211 from the n-type doped region 222 is formed.
  • the contact region 223 is doped with high concentration n-type impurities as the same conductivity type as the n-type doped region.
  • An oxide film 231 and a pad 232 are formed on the surface of the substrate 211.
  • the oxide film 231 for example, a silicon oxide film (SiO 2 ) may be used, but is not limited thereto.
  • the oxide layer 231 may include a contact hole 233 exposing the contact region 223.
  • the contact hole 233 may be formed by patterning the oxide layer 231 through a mask process to remove a portion corresponding to the contact region 223.
  • the pad 232 may be formed by depositing a metal material after the oxide film 231 is formed and patterning it through a mask process.
  • the pad 232 is electrically connected to the photodiode through the contact region 223, thereby applying a bias voltage to the photodiode.
  • a low concentration n ⁇ doping region that is, a low concentration n type doping region 240 is formed in the high concentration n type doping region 222.
  • the low concentration n-type doped region 240 may be formed to fill a portion of the high concentration n-type doped region 222, and may have a shape surrounded by the high concentration n-type doped region 222. .
  • the low concentration n-type doped region 240 has the same depth at substantially the same height as the high concentration n-type doped region 222, and the high concentration n with its outer circumferential surface in contact with the inner circumferential surface of the high concentration n-type doped region 222.
  • the doped region 222 may be configured to be surrounded by a donut shape.
  • the low concentration n-type doped region 240 and the high concentration n-type doped region 222 configured as described above may have a state that is substantially completely enclosed by the depletion layer 224 while being in contact with the depletion layer 224. .
  • Such high concentration n-type doped regions and low concentration n-type doped regions 222 and 240 may be formed in various ways.
  • the high concentration n-type doping regions and the low concentration n-type doping regions 222 and 240 may be formed by performing the high concentration n-type doping in a shape as shown after performing the low concentration n-type doping.
  • the photodiode depletion layer 224 in the case where the low concentration n-type doping region 240 is formed in the high concentration n-type doping region 222 is substantially different from the conventional method in which the low concentration n-type doping region 240 is not configured. Is formed identically.
  • the area of the high concentration n-type doped region 222 is reduced by the area occupied by the low concentration n-type doped region 240.
  • the photodiode capacitance proportional to the area of the high concentration n-type doped region 222 is reduced, the sensitivity can be improved.
  • the case of forming the n-type doped region in the p-type doped region in the configuration of the photodiode may be formed in the n-type doped region.
  • a low-concentration n-type doping region and a high-concentration p-type doping region are formed, and a low-concentration p-type doping region can be formed in the high-concentration p-type doping region.
  • a lightly doped region of the same conductivity type is formed inside the heavily doped n-type or p-type doped region of the photodiode. Accordingly, the depletion layer is formed substantially the same as the case where the low concentration doped region is not formed, so that the fill factor reduction can be prevented.
  • the area of the high concentration doped region is reduced by the area occupied by the low concentration doped region.
  • the photodiode capacitance is reduced and the sensitivity can be improved.

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Abstract

The present invention provides an image sensor comprising a photodiode formed at a substrate and comprising a high-density n- or p-type first doping region and a low-density second doping region having the same conductive type as the first doping region, wherein the first doping region is formed so as to wrap around the second doping region.

Description

포토다이오드를 사용한 이미지센서Image sensor using photodiode
본 발명은 포토다이오드(photodiode)를 사용한 이미지센서에 관한 것으로서, 보다 상세하게는, 필팩터(fill factor)를 유지하면서 감도를 향상시킬 수 있는 이미지센서에 관한 것이다.The present invention relates to an image sensor using a photodiode, and more particularly, to an image sensor capable of improving sensitivity while maintaining a fill factor.
기존에는, 의료나 공업용 X선 촬영에서 필름과 스크린을 이용한 방식이 사용되었다. 이와 같은 경우에는, 촬영된 필름의 현상 및 보관상의 문제 등에 기인하여 비용 및 시간 측면에서 비효율적이었다.Traditionally, film and screen methods have been used in medical and industrial X-ray imaging. In such a case, it was inefficient in terms of cost and time due to development and storage problems of the photographed film.
이를 개선하기 위해, 디지털 방식의 이미지센서가 현재 널리 사용되고 있다. 디지털 방식의 이미지센서에는 매트릭스 형태로 배치되며 입사된 광을 전기적신호로 변환하는 포토다이오드가 형성된 화소가 구성된다. To improve this, digital image sensors are now widely used. The digital image sensor includes a pixel arranged in a matrix form and having a photodiode for converting incident light into an electrical signal.
일반적으로, 포토다이오드는 필팩터(fill factor)를 높이기 위한 측면에서 큰 면적을 갖도록 설계하게 된다. 그런데, 이와 같이 포토다이오드의 면적이 커지게 되면, 접합 커패시턴스 또한 커지게 되어 감도가 저하되는 문제가 발생된다. 이는 X선 조사시간의 증가뿐만 아니라 영상 변환 시간의 증가를 유발하게 된다.In general, the photodiode is designed to have a large area in terms of increasing the fill factor. However, when the area of the photodiode is increased in this manner, the junction capacitance is also increased, resulting in a problem that the sensitivity is lowered. This causes not only an increase in X-ray irradiation time but also an increase in image conversion time.
이를 개선하기 위해, 포토다이오드의 공핍층을 넓게 형성함으로써 커패시턴스를 낮추어 감도를 높이는 방안이 제안되었다. 이와 같은 공핍층 조절은, 고농도 n형 도핑영역의 도핑 농도 및 바이어스 전압 조절을 통해 이루어질 수 있다. 그런데, 바이어스 전압과 도핑 농도는 한계가 존재하는바, 커패시턴스 조절을 통한 감도 향상 또한 제한적일 수 밖에 없다.In order to improve this problem, a method of increasing sensitivity by lowering capacitance by forming a wide depletion layer of a photodiode has been proposed. Such depletion layer control may be achieved by controlling the doping concentration and the bias voltage of the high concentration n-type doping region. However, since the bias voltage and the doping concentration have limitations, the sensitivity improvement through the capacitance adjustment is inevitably limited.
본 발명은 포토다이오드의 필팩터를 유지하면서 감도를 향상시킬 수 있는 방안을 제공하는 데 과제가 있다.The present invention has a problem to provide a way to improve the sensitivity while maintaining the fill factor of the photodiode.
전술한 바와 같은 과제를 달성하기 위해, 본 발명은 기판에 형성되고, 고농도의 n형 또는 p형의 제1도핑영역과 저농도의 상기 제1도핑영역과 동일한 도전형의 제2도핑영역을 포함하는 포토다이오드를 포함하고, 상기 제1도핑영역은 상기 제2도핑영역의 주위를 둘러싸도록 구성된 이미지센서를 제공한다.In order to achieve the above object, the present invention is formed on a substrate, and comprises a first doping region of high concentration n-type or p-type and a second doping region of the same conductivity type as the first doping region of low concentration And a photodiode, wherein the first doped region is configured to surround the second doped region.
여기서, 상기 포토다이오드는 저농도의 상기 제1 및 2도핑영역과 반대되는 도전형의 제3도핑영역을 포함할 수 있다.Here, the photodiode may include a third doped region of a conductive type opposite to the first and second doped regions of low concentration.
상기 포토다이오드는 상기 제1도핑영역과 연결되고 상기 기판 표면으로 연장된 콘택영역을 포함할 수 있다.The photodiode may include a contact region connected to the first doped region and extending to the substrate surface.
다른 측면에서, 본 발명은 기판에 형성된 저농도의 p형 도핑영역과, 상기 저농도의 p형 도핑영역 내에 형성된 고농도의 n형 도핑영역과, 상기 고농도의 n형 도핑영역 내에 형성된 저농도의 n형 도핑영역을 포함하는 포토다이오드와; 상기 고농도의 n형 도핑영역으로부터 상기 기판 표면으로 연장된 콘택영역을 포함하고, 상기 저농도의 n형 도핑영역과 상기 고농도의 n형 도핑영역은 기판 내에 실질적으로 동일한 높이에서 동일한 깊이를 갖고, 상기 저농도의 n형 도핑영역의 외주면이 고농도의 n형 도핑영역의 내주면에 접촉하는 상태로 상기 고농도의 n형 도핑영역에 의해 도넛 형태로 둘러싸여지는 이미지센서를 제공한다.In another aspect, the present invention provides a low concentration p-type doped region formed in a substrate, a high concentration n-type doped region formed in the low concentration p-type doped region, and a low concentration n-type doped region formed in the high concentration n-type doped region. A photodiode comprising a; A contact region extending from the high concentration n-type doped region to the surface of the substrate, wherein the low concentration n-type doping region and the high concentration n-type doping region have the same depth at substantially the same height in the substrate, and the low concentration The present invention provides an image sensor surrounded by a donut shape by a high concentration of n-type doping regions in a state in which an outer circumferential surface of an n-type doping region has a contact with an inner circumference of a high concentration of n-type doping regions.
여기서, 상기 저농도의 p형 도핑영역으로부터 상기 고농도의 n형 도핑영역에 이르는 콘택영역을 포함할 수 있다.The contact region may include a contact region that extends from the low concentration p-type doping region to the high concentration n-type doping region.
또 다른 측면에서, 본 발명은 제1 도전형의 반도체 층에 형성된 제2 도전형의 고농도 도핑영역과, 상기 제2 도전형의 고농도 도핑영역 내에 형성된 제2 도전형의 저농도 도핑영역을 포함하는 포토다이오드를 포함하고, 상기 제2 도전형의 고농도 도핑영역과 상기 제2 도전형의 저농도 도핑영역은 기판 내에 실질적으로 동일한 높이에서 동일한 깊이를 갖고, 상기 저농도의 n형 도핑영역의 외주면이 고농도의 n형 도핑영역의 내주면에 접촉하는 상태로 상기 고농도의 n형 도핑영역에 의해 도넛 형태로 둘러싸여지는 이미지센서를 제공한다.In still another aspect, the present invention provides a photoconductive layer comprising a high concentration doped region of a second conductivity type formed in a semiconductor layer of a first conductivity type and a low concentration doped region of a second conductivity type formed in a high concentration doped region of the second conductivity type. And a diode, wherein the heavily doped region of the second conductivity type and the lightly doped region of the second conductivity type have the same depth at substantially the same height in the substrate, and the outer circumferential surface of the low concentration n-type doped region has a high concentration of n. The present invention provides an image sensor that is surrounded by a donut shape by a high concentration of n-type doping regions in contact with an inner circumferential surface of the type doping region.
여기서, 상기 제1 도전형의 반도체층 표면으로부터 상기 제2 도전형의 고농도 도핑영역에 이르는 콘택영역을 포함할 수 있다.The contact region may include a contact region that extends from the surface of the first conductive semiconductor layer to the heavily doped region of the second conductive semiconductor.
본 발명에 따르면, 포토다이오드의 고농도 n형 또는 p형 도핑영역의 내부에 동일한 도전형의 저농도 도핑영역을 형성한다. 이에 따라, 공핍층은 저농도 도핑영역이 구성되지 않은 경우와 실질적으로 동일하게 형성되어, 필팩터 감소는 방지될 수 있게 된다.According to the present invention, a low concentration doped region of the same conductivity type is formed inside a high concentration n-type or p-type doped region of the photodiode. Accordingly, the depletion layer is formed substantially the same as the case where the low concentration doped region is not formed, so that the fill factor reduction can be prevented.
그리고, 저농도 도핑영역이 차지하는 면적만큼 고농도 도핑영역의 면적은 감소된다. 이로 인해, 포토다이오드 커패시턴스가 감소되어 감도가 향상될 수 있게 된다.Then, the area of the high concentration doped region is reduced by the area occupied by the low concentration doped region. As a result, the photodiode capacitance is reduced and the sensitivity can be improved.
도 1은 본 발명의 실시예에 따른 이미지센서를 사용한 X선 영상장치를 개략적으로 도시한 사시도.1 is a perspective view schematically showing an X-ray imaging apparatus using an image sensor according to an embodiment of the present invention.
도 2 및 3은 각각 본 발명의 실시예에 따른 이미지센서의 포토다이오드 구조를 개략적으로 도시한 단면도 및 평면도.2 and 3 are a cross-sectional view and a plan view schematically showing a photodiode structure of an image sensor according to an embodiment of the present invention, respectively.
이하, 도면을 참조하여 본 발명의 실시예를 상세하게 설명한다.Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
도 1은 본 발명의 실시예에 따른 이미지센서를 사용한 X선 영상장치를 개략적으로 도시한 사시도이고, 도 2 및 3은 각각 본 발명의 실시예에 따른 이미지센서의 포토다이오드 구조를 개략적으로 도시한 단면도 및 평면도이다.1 is a perspective view schematically illustrating an X-ray imaging apparatus using an image sensor according to an embodiment of the present invention, and FIGS. 2 and 3 schematically illustrate a photodiode structure of an image sensor according to an embodiment of the present invention. Sectional and top view.
본 발명의 실시예에 따른 이미지센서(200)를 사용한 X선 영상장치(100)로서는, 다양한 형태나 용도의 X선 영상장치가 사용될 수 있다. 예를 들면, 맘모그래피(mammography) 장치나, CT 장치 등 다양한 X선 영상장치가 사용될 수 있다. 한편, 이하에서는, 설명의 편의를 위해, X선 영상장치로서 치과용 X선 영상장치를 일예로 든다.As the X-ray imaging apparatus 100 using the image sensor 200 according to an embodiment of the present invention, X-ray imaging apparatuses of various forms and uses may be used. For example, various X-ray imaging apparatuses such as a mammography apparatus or a CT apparatus may be used. In the following description, the dental X-ray imaging apparatus is taken as an example as an X-ray imaging apparatus for convenience of explanation.
도 1을 참조하면, 본 발명의 실시예에 따른 X선 영상장치(100)는, 베이스(110), 지지기둥(120), 승강부재(130), 턱 지지부재(140), 회전암 지지부재(150), 회전암(160), 회전암 구동수단(170), X선 발생기(180), 이미지센서(200)를 포함할 수 있다. 1, the X-ray imaging apparatus 100 according to an embodiment of the present invention, the base 110, the support pillar 120, the lifting member 130, the jaw support member 140, the rotary arm support member 150, the rotation arm 160, the rotation arm driving means 170, the X-ray generator 180, and the image sensor 200 may be included.
베이스(110)는 지면 상에 놓여져, 전술한 구성요소들이 설치된 지지기둥(120)을 지지하게 된다. 지지기둥(120)은 베이스(110)와 연결되며, 베이스(110)로부터 수직하게 연장되어 세워진 상태를 갖게 된다.The base 110 is placed on the ground to support the support pillar 120 on which the above-described components are installed. The support pillar 120 is connected to the base 110 and has a state extending vertically from the base 110.
승강부재(130)는 지지기둥(120)에 설치되어, 모터와 같은 구동수단을 통해 지지기둥(120)을 따라 상하 방향으로 승강 동작을 하게 된다. 이와 같은 동작을 통해, 피검자인 환자의 키에 맞게 턱 지지부재(140)의 높이를 조절할 수 있다. The elevating member 130 is installed on the support pillar 120 to move up and down along the support pillar 120 through a driving means such as a motor. Through this operation, the height of the jaw support member 140 can be adjusted according to the height of the patient who is the subject.
턱 지지부재(140)는 승강부재(130)에 설치되며, 환자의 턱을 지지하게 된다. 이와 같은 턱 지지부재(140)에 의해, 피검자의 두부 즉, 피검체가 X선 발생기(180)와 이미지센서(200) 사이에 위치할 수 있게 된다. 회전암 지지부재(150)는 승강부재(130)의 상부에 연결되어 지면과 평행한 방향을 따라 연장되어 있다. Jaw support member 140 is installed on the elevating member 130, it is to support the jaw of the patient. By the jaw support member 140, the head of the subject, that is, the subject can be located between the X-ray generator 180 and the image sensor 200. The rotary arm supporting member 150 is connected to the upper portion of the elevating member 130 and extends in a direction parallel to the ground.
회전암 지지부재(150)의 하부에는 회전암(160)이 연결된다. 이와 같이 연결된 회전암(160)은 회전암 구동수단(170)에 의해, 지면과 수평한 방향으로의 수평 운동이나, 지면에 수직한 회전축을 기준으로 한 회전 운동을 할 수 있게 된다. 회전암(160)은 회전암 지지부재(150)에 연결되는 수평부와, 수평부의 양단에서 하방으로 절곡된 수직부를 포함할 수 있다. The rotary arm 160 is connected to the lower portion of the rotary arm support member 150. The rotary arm 160 connected as described above may perform a horizontal movement in a direction parallel to the ground or a rotational movement based on a rotation axis perpendicular to the ground by the rotary arm driving means 170. The rotary arm 160 may include a horizontal portion connected to the rotary arm supporting member 150 and a vertical portion bent downward at both ends of the horizontal portion.
회전암(160)의 양측 수직부의 내측에는, 서로 마주보도록 배치된 X선 발생기(180)와 이미지센서(200)가 설치될 수 있다. X선 발생기(180)는 X선을 발생시켜 이를 피검체에 조사하는 구성에 해당되는데, 조사된 X선은 피검체를 통과하여 이미지센서(200)에 입사된다.Inside the vertical portions on both sides of the rotary arm 160, the X-ray generator 180 and the image sensor 200 disposed to face each other may be installed. The X-ray generator 180 corresponds to a configuration of generating X-rays and irradiating them to the subject. The irradiated X-rays are incident to the image sensor 200 through the subject.
이미지센서(200)는 피검체를 통과한 X선을 검출하여 이를 전기적 신호로 변환하는 구성에 해당된다. 이미지센서(200)는 평면적으로 사각 형상을 갖게 되는데, 이에 한정되지는 않는다.The image sensor 200 corresponds to a configuration for detecting X-rays passing through the subject and converting the same into an electrical signal. The image sensor 200 may have a rectangular shape in plan, but is not limited thereto.
본 발명의 실시예에 따른 이미지센서(200)로서 X선을 직접 전기적 신호로 변환하는 직접 방식이나, X선을 가시광선으로 변환한 후 가시광선을 전기적 신호로 변환하는 간접 방식 이미지센서가 사용될 수 있다. As an image sensor 200 according to an embodiment of the present invention, a direct method of directly converting X-rays into an electrical signal or an indirect method of converting X-rays into visible light and then converting visible light into an electrical signal may be used. have.
여기서, 간접 방식 이미지센서가 사용되는 경우에, 이미지센서(200)는 X선을 가시광선으로 변환하는 형광체(scintillator)을 구비하게 된다. 이와 같은 경우에, 형광체는 CsI(cesium iodide)로 형성될 수 있는데, 이에 한정되지는 않는다.Here, when an indirect image sensor is used, the image sensor 200 is provided with a phosphor (scintillator) for converting the X-rays to visible light. In this case, the phosphor may be formed of cesium iodide (CsI), but is not limited thereto.
이미지센서(200)는, 예를 들면, CMOS 방식의 기판을 사용할 수 있다. 이미지센서(200)에는 로우방향과 컬럼방향을 따라 화소가 매트릭스 형태로 배치되고, 각 화소에는 입사된 광을 전기적신호로 변환하는 포토다이오드가 구성된다.The image sensor 200 may use, for example, a CMOS substrate. In the image sensor 200, pixels are arranged in a matrix in a row direction and a column direction, and each pixel includes a photodiode for converting incident light into an electrical signal.
한편, 본 발명의 실시예에 따른 포토다이오드에는 고농도 도핑영역 내에 동일한 도전형의 저농도 도핑영역을 구성하게 된다. 이에 따라, 필팩터를 유지하면서 감도를 향상시키게 되는데, 이에 대해 보다 상세하게 설명한다.On the other hand, the photodiode according to the embodiment of the present invention is to form a low concentration doping region of the same conductivity type in a high concentration doping region. Accordingly, the sensitivity is improved while maintaining the fill factor, which will be described in more detail.
이와 관련하여 도 2 및 3을 참조하면, 본 발명의 실시예에 따라 각 화소에 형성된 포토다이오드는, 예를 들면, PN 접촉 포토다이오드로서 기판(211)에 형성된 p형 도핑영역(221)과 n형 도핑영역(222)으로 구성될 수 있다.2 and 3 in this regard, the photodiodes formed in each pixel according to an embodiment of the present invention, for example, p-type doped region 221 and n formed on the substrate 211 as a PN contact photodiode Type doped region 222.
여기서, 기판(211)으로서 실리콘기판이 사용될 수 있는데, 이에 한정되지는 않는다. Here, a silicon substrate may be used as the substrate 211, but is not limited thereto.
p형 도핑영역(221)은 저농도의 p- 도핑영역으로 구성될 수 있다. 여기서, p형 도핑영역(221)은, 고농도의 p+ 기판(211) 상에 에피택셜 성장(epitaxial growth) 방법으로 형성될 수 있다. The p-type doped region 221 may be composed of a lightly doped p− doped region. Here, the p-type doped region 221 may be formed on the high concentration p + substrate 211 by an epitaxial growth method.
n형 도핑영역(222)은 고농도의 n+ 도핑영역으로 구성되며, p형 도핑영역 내에 형성될 수 있다. The n-type doped region 222 may be formed of a high concentration of n + doped region, and may be formed in the p-type doped region.
한편, n형 도핑영역(222)으로부터 기판(211) 표면을 향해 수직한 방향으로 연장된 콘택영역(223)이 형성되어 있다. 이와 같은 콘택영역(223)은 n형 도핑영역과 동일한 도전타입으로서 고농도 n형 불순물로 도핑된다.On the other hand, a contact region 223 extending in a direction perpendicular to the surface of the substrate 211 from the n-type doped region 222 is formed. The contact region 223 is doped with high concentration n-type impurities as the same conductivity type as the n-type doped region.
기판(211) 표면 상에는 산화막(231)과 패드(232)가 형성되어 있다. 산화막(231)으로서는 예를 들면 실리콘산화막(SiO2)이 사용될 수 있는데, 이에 한정되지는 않는다. An oxide film 231 and a pad 232 are formed on the surface of the substrate 211. As the oxide film 231, for example, a silicon oxide film (SiO 2 ) may be used, but is not limited thereto.
산화막(231)은 콘택영역(223)을 노출하는 콘택홀(233)을 포함할 수 있다. 이와 같은 콘택홀(233)은, 마스크 공정을 통해 산화막(231)을 패터닝하여 콘택영역(223)에 대응되는 부분을 제거함으로써 형성될 수 있다.The oxide layer 231 may include a contact hole 233 exposing the contact region 223. The contact hole 233 may be formed by patterning the oxide layer 231 through a mask process to remove a portion corresponding to the contact region 223.
패드(232)는 산화막(231) 형성후에 금속물질을 증착하고 마스크 공정을 통해 패터닝하여 형성될 수 있다. 이와 같은 패드(232)는 콘택영역(223)을 통해 포토다이오드와 전기적으로 연결됨으로써, 바이어스전압을 포토다이오드에 인가할 수 있게 된다.The pad 232 may be formed by depositing a metal material after the oxide film 231 is formed and patterning it through a mask process. The pad 232 is electrically connected to the photodiode through the contact region 223, thereby applying a bias voltage to the photodiode.
한편, 본 발명의 실시예에 따르면, 고농도 n형 도핑영역(222) 내에 저농도의 n- 도핑영역 즉 저농도 n형 도핑영역(240)이 형성된다. 이처럼, 저농도 n형 도핑영역(240)은 고농도 n형 도핑영역(222)의 내부 일부를 채우도록 형성되어, 그 주위가 고농도 n형 도핑영역(222)에 의해 완전히 둘러싸인 형태를 갖게 구성될 수 있다. Meanwhile, according to the exemplary embodiment of the present invention, a low concentration n− doping region, that is, a low concentration n type doping region 240 is formed in the high concentration n type doping region 222. As such, the low concentration n-type doped region 240 may be formed to fill a portion of the high concentration n-type doped region 222, and may have a shape surrounded by the high concentration n-type doped region 222. .
특히, 저농도 n형 도핑영역(240)은 고농도 n형 도핑영역(222)와 실질적으로 동일한 높이에서 동일한 깊이를 가지며, 그 외주면이 고농도 n형 도핑영역(222)의 내주면에 접촉하는 상태로 고농도 n형 도핑영역(222)에 의해 도넛 형태로 둘러싸여지도록 구성될 수 있다. 그리고, 이와 같은 형태로 구성된 저농도 n형 도핑영역(240) 및 고농도 n형 도피영역(222)은 공핍층(224)과 접촉하면서 공핍층(224)에 의해 실질적으로 완전히 밀폐된 상태를 가질 수 있다.In particular, the low concentration n-type doped region 240 has the same depth at substantially the same height as the high concentration n-type doped region 222, and the high concentration n with its outer circumferential surface in contact with the inner circumferential surface of the high concentration n-type doped region 222. The doped region 222 may be configured to be surrounded by a donut shape. In addition, the low concentration n-type doped region 240 and the high concentration n-type doped region 222 configured as described above may have a state that is substantially completely enclosed by the depletion layer 224 while being in contact with the depletion layer 224. .
이와 같은 고농도 n형 도핑영역 및 저농도 n형 도핑영역(222, 240)은 다양한 방법으로 형성될 수 있다. 일예로, 저농도 n형 도핑을 수행한 후에 고농도 n형 도핑을 도시한 바와 같은 형상으로 수행함으로써, 고농도 n형 도핑영역 및 저농도 n형 도핑영역(222, 240)이 형성될 수 있다.Such high concentration n-type doped regions and low concentration n-type doped regions 222 and 240 may be formed in various ways. For example, the high concentration n-type doping regions and the low concentration n- type doping regions 222 and 240 may be formed by performing the high concentration n-type doping in a shape as shown after performing the low concentration n-type doping.
위와 같이, 고농도 n형 도핑영역(222) 내에 저농도 n형 도핑영역(240)을 구성한 경우에서의 포토다이오드 공핍층(224)은, 저농도 n형 도핑영역(240)이 구성되지 않은 종래와 실질적으로 동일하게 형성된다. As described above, the photodiode depletion layer 224 in the case where the low concentration n-type doping region 240 is formed in the high concentration n-type doping region 222 is substantially different from the conventional method in which the low concentration n-type doping region 240 is not configured. Is formed identically.
이에 따라, 광이 입사하게 되면 전자 및 정공의 전하쌍이 충분히 발생된다. 따라서, 저농도 n형 도핑영역(240)을 형성하더라도, 이에 기인한 필팩터 감소는 방지될 수 있게 된다.Accordingly, when light is incident, charge pairs of electrons and holes are sufficiently generated. Therefore, even if the low concentration n-type doped region 240 is formed, the reduction in fill factor due to this can be prevented.
한편, 저농도 n형 도핑영역(240) 형성에 따라, 저농도 n형 도핑영역(240)이 차지하는 면적만큼 고농도 n형 도핑영역(222)의 면적은 감소된다. 이로 인해, 고농도 n형 도핑영역(222)의 면적에 비례하는 포토다이오드 커패시턴스가 감소되므로, 감도가 향상될 수 있게 된다.Meanwhile, as the low concentration n-type doped region 240 is formed, the area of the high concentration n-type doped region 222 is reduced by the area occupied by the low concentration n-type doped region 240. As a result, since the photodiode capacitance proportional to the area of the high concentration n-type doped region 222 is reduced, the sensitivity can be improved.
한편, 전술한 바에서는, 포토다이오드를 구성함에 있어 p형 도핑영역 내에 n형 도핑영역을 형성한 경우를 예로 들었다. 이와는 다른 예로서, n형 도핑영역 내에 p형 도핑영역을 형성할 수 있다. 이와 같은 경우에, 저동도 n형 도핑영역과 고농도 p형 도핑영역이 구성되며, 고농도 p형 도핑영역 내에 저농도 p형 도핑영역이 구성될 수 있게 된다.On the other hand, in the foregoing description, the case of forming the n-type doped region in the p-type doped region in the configuration of the photodiode. As another example, the p-type doped region may be formed in the n-type doped region. In such a case, a low-concentration n-type doping region and a high-concentration p-type doping region are formed, and a low-concentration p-type doping region can be formed in the high-concentration p-type doping region.
전술한 바와 같이, 본 발명의 실시예에 따르면, 포토다이오드의 고농도 n형 또는 p형 도핑영역의 내부에 동일한 도전형의 저농도 도핑영역을 형성한다. 이에 따라, 공핍층은 저농도 도핑영역이 구성되지 않은 경우와 실질적으로 동일하게 형성되어, 필팩터 감소는 방지될 수 있게 된다.As described above, according to the embodiment of the present invention, a lightly doped region of the same conductivity type is formed inside the heavily doped n-type or p-type doped region of the photodiode. Accordingly, the depletion layer is formed substantially the same as the case where the low concentration doped region is not formed, so that the fill factor reduction can be prevented.
그리고, 저농도 도핑영역이 차지하는 면적만큼 고농도 도핑영역의 면적은 감소된다. 이로 인해, 포토다이오드 커패시턴스가 감소되어 감도가 향상될 수 있게 된다.Then, the area of the high concentration doped region is reduced by the area occupied by the low concentration doped region. As a result, the photodiode capacitance is reduced and the sensitivity can be improved.

Claims (7)

  1. 기판에 형성되고, 고농도의 n형 또는 p형의 제1도핑영역과 저농도의 상기 제1도핑영역과 동일한 도전형의 제2도핑영역을 포함하는 포토다이오드를 포함하고,A photodiode formed on the substrate, the photodiode comprising a first doped region having a high concentration and a second doped region having the same conductivity type as the first doped region having a lower concentration;
    상기 제1도핑영역은 상기 제2도핑영역의 주위를 둘러싸도록 구성된Wherein the first doped region is configured to surround the second doped region
    이미지센서.Image sensor.
  2. 제 1 항에 있어서,The method of claim 1,
    상기 포토다이오드는 저농도의 상기 제1 및 2도핑영역과 반대되는 도전형의 제3도핑영역을 포함하는The photodiode includes a third doped region of conductivity type opposite to the first and second doped regions of low concentration.
    이미지센서.Image sensor.
  3. 상기 포토다이오드는 상기 제1도핑영역과 연결되고 상기 기판 표면으로 연장된 콘택영역을 포함하는The photodiode includes a contact region connected to the first doped region and extending to the substrate surface.
    이미지센서.Image sensor.
  4. 기판에 형성된 저농도의 p형 도핑영역과, 상기 저농도의 p형 도핑영역 내에 형성된 고농도의 n형 도핑영역과, 상기 고농도의 n형 도핑영역 내에 형성된 저농도의 n형 도핑영역을 포함하는 포토다이오드와;A photodiode comprising a low concentration p-type doping region formed in the substrate, a high concentration n-type doping region formed in the low concentration p-type doping region, and a low concentration n-type doping region formed in the high concentration n-type doping region;
    상기 고농도의 n형 도핑영역으로부터 상기 기판 표면으로 연장된 콘택영역을 포함하고,A contact region extending from the high concentration n-type doped region to the substrate surface,
    상기 저농도의 n형 도핑영역과 상기 고농도의 n형 도핑영역은 기판 내에 실질적으로 동일한 높이에서 동일한 깊이를 갖고, 상기 저농도의 n형 도핑영역의 외주면이 고농도의 n형 도핑영역의 내주면에 접촉하는 상태로 상기 고농도의 n형 도핑영역에 의해 도넛 형태로 둘러싸여지는The low concentration n-type doped region and the high concentration n-type doped region have the same depth at substantially the same height in the substrate, and the outer circumferential surface of the low concentration n-type doped region is in contact with the inner circumferential surface of the high concentration n-type doped region. Surrounded by a donut shape by the high concentration of n-type doping region
    이미지센서.Image sensor.
  5. 제 4 항에 있어서,The method of claim 4, wherein
    상기 저농도의 p형 도핑영역으로부터 상기 고농도의 n형 도핑영역에 이르는 콘택영역을 포함하는And a contact region from the low concentration p-type doped region to the high concentration n-type doped region.
    이미지센서.Image sensor.
  6. 제1 도전형의 반도체 층에 형성된 제2 도전형의 고농도 도핑영역과, 상기 제2 도전형의 고농도 도핑영역 내에 형성된 제2 도전형의 저농도 도핑영역을 포함하는 포토다이오드를 포함하고,A photodiode comprising a high concentration doped region of a second conductivity type formed in the first conductive semiconductor layer, and a low concentration doped region of a second conductivity type formed in the high concentration doped region of the second conductivity type,
    상기 제2 도전형의 고농도 도핑영역과 상기 제2 도전형의 저농도 도핑영역은 기판 내에 실질적으로 동일한 높이에서 동일한 깊이를 갖고, 상기 저농도의 n형 도핑영역의 외주면이 고농도의 n형 도핑영역의 내주면에 접촉하는 상태로 상기 고농도의 n형 도핑영역에 의해 도넛 형태로 둘러싸여지는The high concentration doped region of the second conductivity type and the low concentration doped region of the second conductivity type have the same depth at substantially the same height in the substrate, and the outer circumferential surface of the low concentration n type doped region has an inner circumferential surface of the high concentration n type doped region. Surrounded by a donut form by the high concentration of n-type doped region in contact with
    이미지센서.Image sensor.
  7. 제 6 항에 있어서,The method of claim 6,
    상기 제1 도전형의 반도체층 표면으로부터 상기 제2 도전형의 고농도 도핑영역에 이르는 콘택영역을 포함하는A contact region extending from the surface of the first conductive semiconductor layer to the heavily doped region of the second conductive type;
    이미지센서.Image sensor.
PCT/KR2014/003787 2013-05-13 2014-04-29 Image sensor using photodiode WO2014185643A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08130299A (en) * 1994-10-31 1996-05-21 Matsushita Electron Corp Ccd solid state image sensor and manufacture thereof
JPH1146010A (en) * 1997-05-27 1999-02-16 Hamamatsu Photonics Kk Avalanche photodiode
JP2000124496A (en) * 1998-10-21 2000-04-28 Nec Corp Semiconductor light reception device and its manufacture
KR100723031B1 (en) * 2005-06-07 2007-05-30 엠텍비젼 주식회사 Image sensor and method of manufacturing it
JP2007201087A (en) * 2006-01-25 2007-08-09 Fujifilm Corp Solid-state image pickup element and manufacturing method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08130299A (en) * 1994-10-31 1996-05-21 Matsushita Electron Corp Ccd solid state image sensor and manufacture thereof
JPH1146010A (en) * 1997-05-27 1999-02-16 Hamamatsu Photonics Kk Avalanche photodiode
JP2000124496A (en) * 1998-10-21 2000-04-28 Nec Corp Semiconductor light reception device and its manufacture
KR100723031B1 (en) * 2005-06-07 2007-05-30 엠텍비젼 주식회사 Image sensor and method of manufacturing it
JP2007201087A (en) * 2006-01-25 2007-08-09 Fujifilm Corp Solid-state image pickup element and manufacturing method thereof

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