JPS6070774A - Detector for radiation - Google Patents
Detector for radiationInfo
- Publication number
- JPS6070774A JPS6070774A JP58178605A JP17860583A JPS6070774A JP S6070774 A JPS6070774 A JP S6070774A JP 58178605 A JP58178605 A JP 58178605A JP 17860583 A JP17860583 A JP 17860583A JP S6070774 A JPS6070774 A JP S6070774A
- Authority
- JP
- Japan
- Prior art keywords
- crystal substrate
- depletion layer
- junction electrode
- detector
- schottky
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005855 radiation Effects 0.000 title claims abstract description 13
- 239000013078 crystal Substances 0.000 claims abstract description 32
- 239000000758 substrate Substances 0.000 claims abstract description 28
- 229910004613 CdTe Inorganic materials 0.000 claims abstract description 22
- 230000004888 barrier function Effects 0.000 claims description 13
- 230000035945 sensitivity Effects 0.000 abstract description 6
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 abstract description 5
- 239000000969 carrier Substances 0.000 abstract description 2
- 230000000694 effects Effects 0.000 abstract description 2
- 230000005684 electric field Effects 0.000 abstract description 2
- 239000010931 gold Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- MODGUXHMLLXODK-UHFFFAOYSA-N [Br].CO Chemical compound [Br].CO MODGUXHMLLXODK-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000003708 ampul Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- FDWREHZXQUYJFJ-UHFFFAOYSA-M gold monochloride Chemical compound [Cl-].[Au+] FDWREHZXQUYJFJ-UHFFFAOYSA-M 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
Classifications
-
- 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
- H01L31/118—Devices sensitive to very short wavelength, e.g. X-rays, gamma-rays or corpuscular radiation of the surface barrier or shallow PN junction detector type, e.g. surface barrier alpha-particle detectors
Abstract
Description
【発明の詳細な説明】
〔発明の属する技術分野〕
本発明は、高比抵抗Ｐ形ＣｄＴｅ結晶基板を用いた放射
線検出器に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a radiation detector using a high resistivity P-type CdTe crystal substrate.
第１図は従来のこの種のＸ線検出器の一例を示す構成斜
視図、第２図は要部断面図である。FIG. 1 is a perspective view of the configuration of an example of a conventional X-ray detector of this type, and FIG. 2 is a sectional view of the main part.
この検出器は、高比抵抗Ｐ形ＣｄＴｅ結晶基板１にショ
ットキ・バリア特性を有する薄膜電極２を形成させると
ともに、これに対向してオーミック接合電極３を形成さ
せて構成したもので、ショットキ・バリア電極２と、Ｃ
ｄＴｅ結晶基板１との接合によって生じた有感層（空乏
層）４を利用して、電極２側から入ってくるＸ線を検出
する。This detector is constructed by forming a thin film electrode 2 having Schottky barrier characteristics on a high resistivity P-type CdTe crystal substrate 1, and forming an ohmic junction electrode 3 opposite to this. Electrode 2 and C
X-rays entering from the electrode 2 side are detected using a sensitive layer (depletion layer) 4 created by bonding with the dTe crystal substrate 1.
この様な構成の従来の検出器においては、接合容量等検
出器が有する容量成分と、シｗｙ）キ。In a conventional detector with such a configuration, capacitance components such as junction capacitance, etc., which the detector has, and
バリアによって生じたＣｄＴａ結晶内の空乏層化してな
い結晶基板Ａの部分の抵抗と、接触抵抗の寄生直列抵抗
が存在し、これらによって、検出器の周波数の周波数応
答特性は決定され、良好な周波数応答特性が得られなか
った。また、検出器の有感層を広げ、Ｘ線感度を上げる
ためには、高比抵抗単結晶を使用する必要があり、基板
抵抗が検出器の直列抵抗を大きくしていた。There is a resistance in the part of the crystal substrate A that is not depleted in the CdTa crystal caused by the barrier, and a parasitic series resistance of the contact resistance, and these determine the frequency response characteristics of the detector, and the frequency response characteristic of the detector is determined by these. Response characteristics could not be obtained. Furthermore, in order to expand the sensitive layer of the detector and increase its X-ray sensitivity, it is necessary to use a high resistivity single crystal, and the substrate resistance increases the series resistance of the detector.
本発明は、高比抵抗Ｐ形ＣｄＴｅ結晶を用い、高い放射
線感度を有し、かつ周波数応答特性の良好な放射線検出
器を実現しようとするものである。The present invention aims to realize a radiation detector that uses a high resistivity P-type CdTe crystal, has high radiation sensitivity, and has good frequency response characteristics.
本発明に係る放射線検出器は、ショットキ・バリア接合
電極下のＣｄＴｅ結晶内に生じる空乏層が、オーミック
接合電極に達するようにＣｄＴｅ結晶基板の厚さを所定
の厚さにした点に構成上あ特徴がある。The radiation detector according to the present invention has a structure in that the thickness of the CdTe crystal substrate is set to a predetermined thickness so that the depletion layer generated in the CdTe crystal under the Schottky barrier junction electrode reaches the ohmic junction electrode. It has characteristics.
第６図は、本発明に係る放射線検出器の一例を示す要部
の側断面図である。この図において、１は例えば３Ｘ１
０５Ωａｍ程度の高比抵抗Ｐ形ＣｄＴｓ結晶基板、２は
このＣｄＴｅ結晶基板上に例えば真空蒸着等の手法によ
って形成しｆｃ）Ｌｔのショットキ・バリア接合電極、
５はＣｄＴｅ結晶基板の他方の面に形成した例えばＡ、
ｕのオーミック接合電極、４はショットキ・バリア電極
１の下に生じた有感層（空乏層）、５は各電極に接続さ
れたリード線である。FIG. 6 is a side sectional view of essential parts showing an example of a radiation detector according to the present invention. In this figure, 1 is, for example, 3X1
A P-type CdTs crystal substrate with a high specific resistance of about 0.05 Ωam, 2 is formed on this CdTe crystal substrate by a method such as vacuum evaporation, and fc) Lt Schottky barrier junction electrode;
5 is formed on the other side of the CdTe crystal substrate, for example, A,
4 is a sensitive layer (depletion layer) formed under the Schottky barrier electrode 1, and 5 is a lead wire connected to each electrode.
本発明の検出器においては、ＣｄＴｅ結晶基板１の厚さ
ｔが、例えば０．２５ｒｎｍ程度の薄さに選定されてお
υ、ショットキ・バリア電極１の下に生じる有感層４が
、オーミック接合電極３まで到達している。In the detector of the present invention, the thickness t of the CdTe crystal substrate 1 is selected to be as thin as, for example, 0.25 nm, so that the sensitive layer 4 formed under the Schottky barrier electrode 1 forms an ohmic contact. It has reached electrode 3.
この様に構成される検出器は、次のようにして作られる
。A detector configured in this manner is manufactured as follows.
まず、ｃｄとＴｅとを化学当量混合し、これを石英ガラ
スアンプルに真空封入した後、垂直ブリッジマン炉で加
熱し、結晶化して得られた単結晶インゴットを、ウェハ
状に切断する。これを、約０．３ｍｍの厚さまで研摩し
、ブロムメタノール液で化学エッチし、厚さ０．２５ｍ
ｍのＣｄＴｅ結晶基板を作る。次に、とのＣｄＴｅ結晶
基板の表面を、Ａｒイオンでスパッタエッチし、清浄化
した後、ａを厚さ２０ｎｒｎ真空蒸着し、ショットキ・
バリア接合電極２を形成する。First, CD and Te are mixed in chemical equivalents, vacuum sealed in a quartz glass ampoule, heated in a vertical Bridgman furnace, and the resulting single crystal ingot is cut into wafers. This was polished to a thickness of about 0.3 mm, chemically etched with a bromine methanol solution, and made to a thickness of 0.25 mm.
A CdTe crystal substrate of m is made. Next, the surface of the CdTe crystal substrate was sputter-etched with Ar ions and cleaned, and then a 20nrn thick film was vacuum-deposited with Schottky.
A barrier junction electrode 2 is formed.
続いて、ＣｄＴｅ結晶基板の他の表面に、塩化金を塗布
して、Ａｕオーミック電極３を形成する。次に信号取り
出しのためのリード線５ｆ、例えば導電性接着剤によっ
て各電極２，５に結合して完成する。Subsequently, gold chloride is applied to the other surface of the CdTe crystal substrate to form an Au ohmic electrode 3. Next, a lead wire 5f for signal extraction is connected to each electrode 2, 5 using, for example, a conductive adhesive to complete the process.
第３図に示す検出器において、Ａｔショットキ・バリア
接合電極２側から、放射線がＣｄＴｅ結晶基板１内に入
射すると、空乏層４内に発生した自由キャリアは、空乏
層４内の電界で加速され、ａショエ
ノトキ・バリア接合電極２に到達し、電離電流／が
メリード線５を介して得られる。ここで、本発明におい
ては、空乏層４がＡｕオーミック接合電極３まで到達し
ているので、検出器の直列抵抗成分には、本質的ＫＰ形
ＣｄＴｅ結晶基板１自体の抵抗は含まれない。このため
、結晶基板１の比抵抗が太きくなるほど、ショットキ・
バリア接合によって生じる空乏層４が大きくなり、感度
が上がると同時に、ＣｄＴｅ結晶基板１の厚さｔを空乏
層４の幅とすることで、大きな基板抵抗が検出器の直列
抵抗成分にほとんど影響しなくなる。従って、検出器の
直列抵抗成分と接合容量等の容量で決まる検出器の周波
数応答特性を改善することができる。In the detector shown in FIG. 3, when radiation enters the CdTe crystal substrate 1 from the At Schottky barrier junction electrode 2 side, free carriers generated in the depletion layer 4 are accelerated by the electric field in the depletion layer 4. , a reaches the barrier junction electrode 2, and an ionizing current / is obtained via the lead wire 5. In the present invention, since the depletion layer 4 reaches the Au ohmic junction electrode 3, the series resistance component of the detector does not essentially include the resistance of the KP type CdTe crystal substrate 1 itself. Therefore, the thicker the specific resistance of the crystal substrate 1, the Schottky
The depletion layer 4 generated by the barrier junction becomes larger, increasing the sensitivity. At the same time, by setting the thickness t of the CdTe crystal substrate 1 to the width of the depletion layer 4, the large substrate resistance hardly affects the series resistance component of the detector. It disappears. Therefore, the frequency response characteristic of the detector, which is determined by the series resistance component of the detector and the capacitance such as the junction capacitance, can be improved.
第４図は、結晶基板の厚さｔを１５５ｍｍ、 ０．５３
ｍｒｎ。In Figure 4, the thickness t of the crystal substrate is 155 mm, 0.53
mrn.
０．２５ｍｍと変えてめた周波数応答特性を示す。この
実験結果によれば、厚さｔｆ Ｏ，２５ｒｎｍとしたも
の、すなわち、空乏層がオーミック接合電極に達するよ
うに構成したものが、最も周波数応答特性が良好であっ
た。The frequency response characteristics obtained by changing the width to 0.25 mm are shown. According to the experimental results, the one with a thickness of tf O of 25 nm, that is, the one configured so that the depletion layer reached the ohmic junction electrode, had the best frequency response characteristics.
以上説明したように、本発明によれば、高い放射線感度
を有し、周波数応答特性の良好な放射線検出器が実現で
きる。As explained above, according to the present invention, a radiation detector having high radiation sensitivity and good frequency response characteristics can be realized.
第１図は従来の検出器の一例を示す構成斜視図、第２図
はその要部断面図、第５図は本発明に係る検出器の一例
を示す要部の側面断面図、第４図は実験結果の一例を示
す特性線図である。
１・・・Ｐ形ＣｄＴｅ結晶基板、２・・・ショットキ・
バリア接合電極、３・・・オーミック接合電極、４・・
・空乏層、５・・・リード線。FIG. 1 is a perspective view of the configuration of an example of a conventional detector, FIG. 2 is a cross-sectional view of the main parts thereof, FIG. 5 is a side cross-sectional view of the main parts of an example of the detector according to the present invention, and FIG. is a characteristic diagram showing an example of experimental results. 1... P-type CdTe crystal substrate, 2... Schottky
Barrier junction electrode, 3... Ohmic junction electrode, 4...
・Depletion layer, 5... Lead wire.
Claims (1)
ットキ・バリア接合電極を形成するとともに他方の面に
オーミンク接合電極を形成させた放射線検出器において
、 前記Ｐ形ＣｄＴｅ結晶基板の厚さを、前記ショットキ・
バリア接合電極下のＣｄＴａ結晶内に生ずる空乏層が、
前記オーミック接合電極に達するように所定の厚さに選
定したことを特徴とする放射線検出器。(1) In a radiation detector in which a Schottky barrier junction electrode is formed on one surface of a high resistivity P-type CdTe crystal substrate and an Ohmink junction electrode is formed on the other surface, the thickness of the P-type CdTe crystal substrate , the Schottky
The depletion layer generated in the CdTa crystal under the barrier junction electrode is
A radiation detector characterized in that a predetermined thickness is selected so as to reach the ohmic junction electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58178605A JPS6070774A (en) | 1983-09-27 | 1983-09-27 | Detector for radiation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58178605A JPS6070774A (en) | 1983-09-27 | 1983-09-27 | Detector for radiation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6070774A true JPS6070774A (en) | 1985-04-22 |
Family
ID=16051371
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58178605A Pending JPS6070774A (en) | 1983-09-27 | 1983-09-27 | Detector for radiation |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6070774A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6314479A (en) * | 1986-07-07 | 1988-01-21 | Nippon Mining Co Ltd | Cdte radiation detecting element |
| EP1691422A1 (en) * | 2003-11-27 | 2006-08-16 | Nagoya Industrial Science Research Institute | Semiconductor radiation detector and process for producing the same |
| WO2010134493A1 (en) * | 2009-05-19 | 2010-11-25 | Sasaki Takehisa | Radiation detecting element and radiation detecting device |
| JP2014099621A (en) * | 2013-12-11 | 2014-05-29 | Takehisa Sasaki | Radiation detecting element and radiation detecting device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5661179A (en) * | 1979-10-24 | 1981-05-26 | Fuji Electric Co Ltd | Preparation of semiconductor radiation detector |
-
1983
- 1983-09-27 JP JP58178605A patent/JPS6070774A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5661179A (en) * | 1979-10-24 | 1981-05-26 | Fuji Electric Co Ltd | Preparation of semiconductor radiation detector |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6314479A (en) * | 1986-07-07 | 1988-01-21 | Nippon Mining Co Ltd | Cdte radiation detecting element |
| JPH0734480B2 (en) * | 1986-07-07 | 1995-04-12 | 株式会社ジャパンエナジー | CdTe radiation detection element |
| EP1691422A1 (en) * | 2003-11-27 | 2006-08-16 | Nagoya Industrial Science Research Institute | Semiconductor radiation detector and process for producing the same |
| EP1691422A4 (en) * | 2003-11-27 | 2008-12-24 | Inst Nagoya Ind Science Res | Semiconductor radiation detector and process for producing the same |
| WO2010134493A1 (en) * | 2009-05-19 | 2010-11-25 | Sasaki Takehisa | Radiation detecting element and radiation detecting device |
| JP2010272577A (en) * | 2009-05-19 | 2010-12-02 | Takehisa Sasaki | Radiation detecting element and radiation detector |
| US8674358B2 (en) | 2009-05-19 | 2014-03-18 | Takehisa Sasaki | Radiation detecting element and radiation detecting device |
| US9054260B2 (en) | 2009-05-19 | 2015-06-09 | Takehisa Konda | Radiation detecting element and radiation detecting device |
| JP2014099621A (en) * | 2013-12-11 | 2014-05-29 | Takehisa Sasaki | Radiation detecting element and radiation detecting device |
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