WO2016143156A1 - 放射線検出器およびそれを用いた放射線検出装置 - Google Patents
放射線検出器およびそれを用いた放射線検出装置 Download PDFInfo
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- WO2016143156A1 WO2016143156A1 PCT/JP2015/069453 JP2015069453W WO2016143156A1 WO 2016143156 A1 WO2016143156 A1 WO 2016143156A1 JP 2015069453 W JP2015069453 W JP 2015069453W WO 2016143156 A1 WO2016143156 A1 WO 2016143156A1
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- radiation
- semiconductor region
- sensitive layer
- impurity concentration
- radiation detector
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- 230000005855 radiation Effects 0.000 title claims abstract description 170
- 238000001514 detection method Methods 0.000 title claims description 15
- 239000004065 semiconductor Substances 0.000 claims abstract description 150
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- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims abstract description 16
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/24—Measuring radiation intensity with semiconductor detectors
- G01T1/241—Electrode arrangements, e.g. continuous or parallel strips or the like
-
- 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
- H01L31/0248—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 characterised by their semiconductor bodies
- H01L31/0256—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 characterised by their semiconductor bodies characterised by the material
- H01L31/0264—Inorganic materials
- H01L31/0312—Inorganic materials including, apart from doping materials or other impurities, only AIVBIV compounds, e.g. SiC
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/24—Measuring radiation intensity with semiconductor detectors
-
- 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
- H01L31/02—Details
- H01L31/02016—Circuit arrangements of general character for the devices
- H01L31/02019—Circuit arrangements of general character for the devices for devices characterised by at least one potential jump barrier or surface barrier
-
- 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
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
-
- 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 at least one potential-jump barrier or surface barrier, e.g. phototransistors
- H01L31/115—Devices sensitive to very short wavelength, e.g. X-rays, gamma-rays or corpuscular radiation
-
- 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 at least one potential-jump barrier or surface barrier, e.g. phototransistors
- H01L31/115—Devices sensitive to very short wavelength, e.g. X-rays, gamma-rays or corpuscular radiation
- H01L31/117—Devices sensitive to very short wavelength, e.g. X-rays, gamma-rays or corpuscular radiation of the bulk effect radiation detector type, e.g. Ge-Li compensated PIN gamma-ray detectors
Definitions
- the present invention relates to a radiation detector using silicon carbide.
- a radiation detector capable of analyzing the energy of incident radiation is mainly used in combination with a scintillator and a photomultiplier tube.
- a radiation detector for detecting radiation such as gamma rays.
- a semiconductor radiation detection technique in which a radiation detector is composed of a semiconductor crystal such as CdTe (cadmium telluride) or GaAs (gallium arsenide) has attracted attention.
- the semiconductor radiation detector includes the semiconductor crystal and electrodes formed on both sides thereof, and radiation such as X-rays and ⁇ rays is incident on the semiconductor crystal by applying a DC voltage between the electrodes. Sometimes, the electric charge generated by the interaction between the radiation and the semiconductor crystal is taken out from the electrode as an electric signal.
- the semiconductor radiation detector has features such as higher energy resolution than that using a scintillator, and can be miniaturized.
- the semiconductor radiation detector detects electric charges generated by radiation incident on the radiation sensitive layer as an electric signal, there is a problem that if the leakage current that flows due to the application of the DC voltage is large, noise is generated and the detection characteristics deteriorate. .
- the detection signal depends on the volume of the radiation-sensitive layer, an area of about 0.1 cm 2 or more and a thickness of about 30 to 50 ⁇ m or more are required for practical use. For this reason, a pn junction that forms a junction inside the substrate is more suitable than a Schottky junction that is susceptible to process defects and dust.
- Non-patent Document 2 Since silicon carbide semiconductor (SiC) has a large band gap of about 3 eV, a pn diode formed of SiC can suppress leakage current even in a high temperature environment such as 175 ° C. (non-patent) Reference 1). It is also known that a PiN diode having a thick n ⁇ epitaxial layer (100 ⁇ m, impurity concentration 2 ⁇ 10 14 cm ⁇ 3 ) can be applied as a radiation detector (Non-patent Document 2).
- Ahmed Elasser et al. “Static and Dynamic Characterisation of 6.5-kV 100-A SiC Bipolar PiN Diode Modules”, IEEE Transactions on Industrial Applications. 50, 609-619, 2014. Bernard F. Phlips et al. , “Silicon Carbide PiN Diodes as Radiation Detectors”, IEEE Nuclear Science Symposium Conference Record, 2005, 1236-1239.
- SiC has a high dielectric breakdown electric field strength and a high impurity concentration, it has an advantageous characteristic as a power semiconductor such that a low-resistance element can be manufactured even with the same breakdown voltage compared to a Si (silicon) semiconductor.
- the depletion layer does not spread over the entire n ⁇ epitaxial layer having a thickness of about 30 to 50 ⁇ m or more, which becomes a radiation sensitive layer. Since the electric field is not applied to the entire n ⁇ epitaxial layer, there is a problem in that the detected electrical signal is reduced.
- the present invention has a structure in which an electric field is applied to the entire SiC crystal serving as a radiation sensitive layer, and detects radiation while suppressing a decrease in electrical signal generated in the radiation sensitive layer. Objective.
- the present invention has a structure in which an electric field is applied to the entire SiC crystal serving as a radiation-sensitive layer at a voltage during operation.
- a radiation-sensitive layer made of silicon carbide and generating electron-hole pairs upon incidence of radiation is in contact with the first main surface of the radiation-sensitive layer.
- a first semiconductor region having a first impurity concentration at least in a region in contact with the radiation sensitive layer, a second main surface opposite to the first main surface, and at least in a region in contact with the radiation sensitive layer.
- a second semiconductor region having two impurity concentrations, a first electrode connected to the first semiconductor region, and a second electrode connected to the second semiconductor region, with the first main surface as a boundary,
- the radiation-sensitive layer adjacent to the second semiconductor region, the impurity concentration in the radiation-sensitive layer adjacent to the first semiconductor region being discontinuous with the first impurity concentration and bordering on the second main surface
- the impurity concentration in the It is discontinuous and the impurity concentration, and is characterized in that the radiation the sensitive layer is electric field is applied across the depth direction at the voltage during operation.
- the radiation detector of the present invention has a structure in which an electric field is applied to the entire SiC crystal serving as a radiation-sensitive layer at an operating voltage, it detects radiation while suppressing a decrease in electrical signals generated in the radiation-sensitive layer. be able to.
- FIG. 3 is an explanatory diagram of a cross-sectional structure in the manufacturing process of the radiation detector subsequent to FIG. 2.
- FIG. 4 is an explanatory diagram of a cross-sectional structure in the manufacturing process of the radiation detector subsequent to FIG. 3.
- FIG. 6 is an explanatory diagram of a cross-sectional structure in the manufacturing process of the radiation detector subsequent to FIG. 5.
- FIG. 1 is an explanatory diagram showing a cross-sectional structure of the radiation detector according to Embodiment 1 of the present invention.
- the radiation detector according to the first embodiment has a first conductivity type low impurity concentration (n ⁇ ) SiC radiation formed on a first conductivity type (n type) high impurity concentration (n + ) SiC substrate 1.
- the second conductivity type (p-type) high impurity concentration (p + ) semiconductor region 3 Provided on the back surface of the sensitive layer 2, the second conductivity type (p-type) high impurity concentration (p + ) semiconductor region 3, the first electrode 4 provided on the surface of the p + semiconductor region 3, and the n + SiC substrate 1.
- the radiation detector has a pn junction provided with the second electrode 5 formed. Further, in this radiation detector, a higher voltage is applied to the second electrode 5 during operation than the first electrode 4, and a depletion layer spreads in the entire depth direction of the n ⁇ SiC radiation sensitive layer 2, so that an electric field is applied. I
- FIGS. 2 to 4 are cross-sectional structure explanatory views in the manufacturing process showing an example of the manufacturing process of the first embodiment.
- the impurity concentration of the n + SiC substrate 1 is in the range of about 1 ⁇ 10 18 to 1 ⁇ 10 19 cm ⁇ 3 .
- the (0001) plane, (000-1) plane, (11-20) plane, etc. are often used as the main surface of the SiC substrate, the present invention is effective regardless of the selection of these main surfaces of the SiC substrate. Can be played.
- the specification of the n ⁇ SiC radiation sensitive layer 2 on the n + SiC substrate 1 may be set to a concentration and a film thickness in which the depletion layer spreads in the entire depth direction by operating voltage. If it is set to 1000 V or less, which is practically suitable, the impurity concentration N is the same conductivity type as the substrate and is in the range of about 3 ⁇ 10 13 to 1.2 ⁇ 10 15 cm ⁇ 3 , and the thickness W is about 30 to 200 ⁇ m. Set the range.
- the relationship between the impurity concentration N, the thickness W, and the operating voltage V is expressed by the following Equation 1 when the p + semiconductor region 3 has a sufficiently high impurity concentration as compared with the impurity concentration of the n ⁇ SiC radiation sensitive layer 2. It is.
- Equation 1 q is an elementary charge, ⁇ is a relative dielectric constant, and ⁇ 0 is a vacuum dielectric constant.
- the relationship between the impurity concentration N and the thickness W is shown in FIG.
- the curve in FIG. 9 shows the thickness of punch-through at 1000 V for each impurity concentration. Since the concentration of the n ⁇ SiC radiation sensitive layer 2 is significantly lower than that of the p + semiconductor region 3, it is assumed that the depletion layer extends only to the n ⁇ SiC radiation sensitive layer 2. Further, since 1000 V is sufficiently larger than the built-in potential, it is assumed that the depletion layer spreads only by a voltage applied during operation (here, 1000 V).
- a metal 4 ′ that forms silicide by reacting with SiC such as nickel (Ni) or titanium (Ti) is deposited on the surface of the p + semiconductor region 3 by sputtering, and then silicidized. Annealing is performed to form the first electrode 4 on the surface of the p + semiconductor region 3.
- the second electrode 5 By forming the second electrode 5 on the back surface of the SiC substrate 1, the main part of the radiation detector of the present invention shown in FIG. 1 is completed.
- the first electrode 4 and the second electrode 5 are opaque electrodes.
- the first electrode 4 covers the p + semiconductor region 3, and the second electrode 5 covers the n + SiC substrate 1.
- FIG. 10 shows an example of a block diagram showing a radiation detection apparatus using the radiation detector in the first exemplary embodiment.
- a pulsed detection current flows.
- the detected current is amplified by the preamplifier 12 and the main amplifier 13 and then measured as a wave height distribution by the multiple wave height analyzer 14. Based on the measured wave height distribution, peak energy analysis can be performed using an analysis device 15 such as a personal computer (PC) to evaluate the radionuclide and the amount thereof.
- PC personal computer
- silicide is directly formed on the surface of the p + semiconductor region 3 and the back surface of the n + SiC substrate 1, but the same polarity as each semiconductor layer is used to reduce the contact resistance between the semiconductor layer and the electrode.
- Impurities that become may be added by an ion implantation method.
- Al is used as a dopant and implantation is performed in multiple stages with different acceleration energies.
- the impurity concentration in the vicinity of the surface is about 1 ⁇ 10 20 cm ⁇ 3 , which is higher than the impurity concentration in the p + semiconductor region 3.
- the region depth is added so as to be about 0.3 ⁇ m.
- the condition of addition is not limited, but the penetration depth of the added impurity is made shallower than the thickness of the p + semiconductor region 3. .
- N nitrogen
- P phosphorus
- N is used as a dopant, and implantation is performed in multiple stages with different acceleration energies.
- the impurity concentration near the surface is about 1 ⁇ 10 20 cm ⁇ 3 , which is higher than the impurity concentration of the n + SiC substrate 1.
- the region depth is added so as to be about 0.5 ⁇ m. If the contact resistance between the n + SiC substrate 1 and the second electrode 5 is reduced, the condition of addition is not limited, but the penetration depth of the added impurity is made shallower than the thickness of the n + SiC substrate 1. . As a result, it is possible to prevent the n ⁇ SiC radiation sensitive layer 2 from being damaged due to the intrusion of the added impurities, and it is possible to prevent a decrease in sensitivity due to the disappearance of carriers.
- an impurity when added to the p + semiconductor region 3 or the n + SiC substrate 1, it may be limited to a part of the region.
- a pattern in which a predetermined region is opened is formed using ordinary lithography and mask material 6, and then p + impurity 3 ′ is added to p + semiconductor region 3.
- the mask material 6 may be any material that can serve as a mask during ion implantation, such as SiO 2 , silicon nitride, a polycrystalline silicon film, or a resist material.
- SiO 2 is used as the mask material 6.
- a pattern in which a predetermined region is opened is formed using ordinary lithography and mask material 6, and then n + impurity 1 ′ is added to n + SiC substrate 1. Further, the step of adding impurities may be performed on the n + SiC substrate 1 first and then on the p + semiconductor region 3. After the impurities are added in this way, a process for forming the first electrode 4 and the second electrode 5 may be performed as shown in FIG.
- the metals 4 ′ and 5 ′ that form silicide by reacting with SiC are deposited by sputtering, silicidation annealing is performed to form the first electrode 4 and the second electrode 5.
- an electrode material such as Al or Au may be further deposited on the first electrode 4 and the second electrode 5.
- the back surface and front surface electrodes are formed immediately.
- the oxidation treatment and the oxide film removal treatment are performed, and the damage on the surface of the p + semiconductor region 3 and the n + SiC substrate 1 is detected.
- a sacrificial oxidation step for removing the layer may be performed.
- the first embodiment it was performed immediately electrode formed on the back surface and the surface, p + surface protective film such as SiO 2 formed by the CVD method on the surface of the semiconductor region 3, the p + semiconductor region 3 The surface may be protected. In this case, after the surface protective film is formed, processing is performed so that only the region where the first electrode 4 is formed is opened.
- the radiation-sensitive layer made of silicon carbide and generating electron-hole pairs upon incidence of radiation is in contact with the first main surface of the radiation-sensitive layer, and at least the radiation-sensitive layer and A first semiconductor region of a first conductivity type having a first impurity concentration in a region in contact with the second main surface opposite to the first main surface, and at least a second impurity concentration in a region in contact with the radiation-sensitive layer; A second conductive region having a second conductivity type, a first electrode connected to the first semiconductor region, and a second electrode connected to the second semiconductor region, wherein the radiation detection layer has a first conductivity.
- a radiation detector that is a type semiconductor, wherein the impurity concentration in the radiation-sensitive layer adjacent to the first semiconductor region is discontinuous with the first impurity concentration, with the first main surface as a boundary, With the second main surface as a boundary, the first Since the impurity concentration in the radiation-sensitive layer adjacent to the semiconductor region is discontinuous with the second impurity concentration, and the radiation-sensitive layer is applied with an electric field in the entire depth direction at the operating voltage, the radiation Radiation can be detected while suppressing a decrease in the electrical signal generated in the sensitive layer.
- FIG. 8 shows a cross-sectional structure of the radiation detector according to the second exemplary embodiment of the present invention.
- a semi-insulating SiC substrate is used as the radiation sensitive layer.
- the radiation-sensitive layer is a semi-insulating SiC substrate 7 having a resistivity of 1 ⁇ 10 5 ⁇ cm 2 or more, and ap + semiconductor region on the upper surface of the semi-insulating SiC substrate 7.
- the n + semiconductor region 8 is provided on the back surface of the semi-insulating SiC substrate 7. That is, SiC is obtained by forming the p + semiconductor region 3 on the semi-insulating SiC substrate 7 having a thickness of about 100 to 500 ⁇ m by epitaxial growth and forming the n + semiconductor region 8 on the back surface of the semi-insulating SiC substrate 7 by epitaxial growth. Prepare the board.
- the first electrode 4 is formed on the p + semiconductor region 3, and the second electrode 5 is formed on the n + semiconductor region 8. Since the radiation sensitive layer is the semi-insulating SiC substrate 7, an electric field is applied to the entire radiation sensitive layer at a voltage during operation of 1000 V or less. Further, since the first electrode 4 and the second electrode 5 are formed on the epitaxial growth layer, the radiation-sensitive layer is not damaged by the addition of impurities and the effect is essentially the same as in the first embodiment. It is.
- the radiation-sensitive layer made of silicon carbide and generating electron-hole pairs upon incidence of radiation is in contact with the first main surface of the radiation-sensitive layer, and at least the radiation-sensitive layer and A first semiconductor region of a first conductivity type having a first impurity concentration in a region in contact with the second main surface opposite to the first main surface, and at least a second impurity concentration in a region in contact with the radiation-sensitive layer; A second conductive region having a second conductivity type, a first electrode connected to the first semiconductor region, and a second electrode connected to the second semiconductor region, wherein the radiation-sensitive layer is semi-insulating.
- a radiation detector that is a conductive silicon carbide substrate, wherein the impurity concentration in the radiation-sensitive layer adjacent to the first semiconductor region is discontinuous with the first impurity concentration with the first main surface as a boundary. Yes, before the second main surface Since the impurity concentration in the radiation sensitive layer adjacent to the second semiconductor region is discontinuous with the second impurity concentration, and the radiation sensitive layer is applied with an electric field in the entire depth direction at the operating voltage. The radiation can be detected while suppressing a decrease in the electrical signal generated in the radiation sensitive layer.
- the present invention has been described using the first and second embodiments.
- the technique such as addition of additional impurities described using the first embodiment can also be applied.
Abstract
Description
図1は、本発明の実施の形態1における放射線検出器の断面構造を示す説明図である。本実施の形態1による放射線検出器は、第1導電型(n型)の高不純物濃度(n+)SiC基板1上に形成される第1導電型の低不純物濃度(n-)SiC放射線有感層2と、第2導電型(p型)の高不純物濃度(p+)半導体領域3と、p+半導体領域3表面に設けられた第1電極4と、n+SiC基板1裏面に設けられた第2電極5とを備えているpn接合を有する放射線検出器である。さらに、この放射線検出器には、第1電極4と比べて第2電極5に高い電圧が動作時にかかっており、n-SiC放射線有感層2の深さ方向全体に空乏層が広がって電界がかかっている。
数式1において、qは素電荷、εは比誘電率、ε0は真空の誘電率を示す。
図8に、本発明の実施の形態2における放射線検出器の断面構造を示す。実施の形態2は、放射線有感層として半絶縁性SiC基板を用いるものである。
1’ n+不純物
2 n-SiC放射線有感層
3 p+半導体領域
3’ p+不純物
4 第1電極
4’ 金属
5 第2電極
5’ 金属
6 マスク材
7 半絶縁性SiC基板
8 n+半導体領域
9 放射線検出器
11 高圧電源
12 プリアンプ
13 メインアンプ
14 多重波高分析装置
15 解析装置
Claims (15)
- 炭化珪素からなり、放射線の入射によって電子正孔対を生成する放射線有感層と、
前記放射線有感層の第1主面で接し、少なくとも前記放射線有感層と接する領域において第1不純物濃度を有する第1半導体領域と、
前記第1主面と反対側の第2主面で接し、少なくとも前記放射線有感層と接する領域において第2不純物濃度を有する第2半導体領域と、
前記第1半導体領域と接続する第1電極と、
前記第2半導体領域と接続する第2電極と、を備え、
前記第1主面を境として、前記第1半導体領域と隣接する前記放射線有感層内の不純物濃度が前記第1不純物濃度と不連続であり、
前記第2主面を境として、前記第2半導体領域と隣接する前記放射線有感層内の不純物濃度が前記第2不純物濃度と不連続であり、
前記放射線有感層が動作時の電圧において深さ方向全体に電界がかかっていることを特徴とする放射線検出器。 - 請求項1に記載の放射線検出器において、
前記第1半導体領域が第1導電型を有し、前記第2半導体領域が前記第1導電型と反対の第2導電型を有することを特徴とする放射線検出器。 - 請求項1に記載の放射線検出器において、
前記放射線有感層が第1導電型の第3不純物濃度を有する半導体であることを特徴とする放射線検出器。 - 請求項3に記載の放射線検出器において、
前記第3不純物濃度は前記第1不純物濃度よりも低いことを特徴とする放射線検出器。 - 請求項4に記載の放射線検出器において、
前記第1半導体領域が第1導電型の炭化珪素基板であり、
前記放射線有感層が第1導電型のエピタキシャル成長層であり、
前記第2半導体領域が第2導電型のエピタキシャル成長層であることを特徴とする放射線検出器。 - 請求項2に記載の放射線検出器において、
前記放射線有感層が半絶縁性の炭化珪素基板であり、
前記第1半導体領域が第1導電型のエピタキシャル成長層であり、
前記第2半導体領域が第2導電型のエピタキシャル成長層であることを特徴とする放射線検出器。 - 請求項6に記載の放射線検出器において、
前記半絶縁性の炭化珪素基板が1×105Ωcm以上の抵抗率を有することを特徴とする放射線検出器。 - 請求項1に記載の放射線検出器において、
前記第1半導体領域と前記第2半導体領域の少なくともどちらか一方に各導電型と同一極性となる不純物をイオン注入によって添加し、前記イオン注入によって添加する不純物の注入深さは前記第1半導体領域もしくは前記第2半導体領域の厚さよりも浅いことを特徴とする放射線検出器。 - 請求項1に記載の放射線検出器において、
前記動作時の電圧が、1000V以下であることを特徴とする放射線検出器。 - 請求項1の放射線検出器と、前記第1電極と前記第2電極との間に電圧を加える高圧電源と、を備える放射線検出装置。
- 請求項11に記載の放射線検出装置において、更に、
検出電流から波高の分布を測定する波高分析装置を備える放射線検出装置。 - 請求項1に記載の放射線検出器において、
前記第1電極は不透明電極であり、
前記第2電極は不透明電極であり、
前記第1半導体領域は前記第1電極に覆われ、
前記第2半導体領域は前記第2電極に覆われていることを特徴とする放射線検出器。 - 炭化珪素の放射線有感層と、
前記放射線有感層の第1主面で接し、少なくとも前記放射線有感層と接する領域において第1不純物濃度を有する第1半導体領域と、
前記第1主面と反対側の第2主面で接し、少なくとも前記放射線有感層と接する領域において第2不純物濃度を有する第2半導体領域と、
前記第1半導体領域を覆う第1不透明電極と、
前記第2半導体領域を覆う第2不透明電極と、を備え、
前記第1主面を境として、前記第1半導体領域と隣接する前記放射線有感層内の不純物濃度が前記第1不純物濃度と不連続であり、
前記第2主面を境として、前記第2半導体領域と隣接する前記放射線有感層内の不純物濃度が前記第2不純物濃度と不連続であることを特徴とする放射線検出器。 - 請求項14の放射線検出器と、前記第1不透明電極と前記第2不透明電極との間に電圧を加える高圧電源と、を備える放射線検出装置。
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