JPH04367597A - Production of cdte single crystal - Google Patents
Production of cdte single crystalInfo
- Publication number
- JPH04367597A JPH04367597A JP16748491A JP16748491A JPH04367597A JP H04367597 A JPH04367597 A JP H04367597A JP 16748491 A JP16748491 A JP 16748491A JP 16748491 A JP16748491 A JP 16748491A JP H04367597 A JPH04367597 A JP H04367597A
- Authority
- JP
- Japan
- Prior art keywords
- single crystal
- cdte
- resistivity
- ppm
- crystal
- 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.)
- Granted
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 30
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 229910004613 CdTe Inorganic materials 0.000 claims abstract description 22
- 239000011261 inert gas Substances 0.000 claims abstract description 5
- 238000010438 heat treatment Methods 0.000 claims description 14
- 238000001816 cooling Methods 0.000 abstract description 3
- 230000005855 radiation Effects 0.000 description 9
- 238000001514 detection method Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 235000012431 wafers Nutrition 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000000370 acceptor Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
Landscapes
- Measurement Of Radiation (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
Description
【０００１】0001
【発明の技術分野】本発明は、放射線検出素子用等とし
て有用な高抵抗ＣｄＴｅ単結晶の製造方法に関する。TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a high resistance CdTe single crystal useful for use in radiation detection elements and the like.
【０００２】0002
【従来技術】ＣｄＴｅ単結晶は室温動作が可能な放射線
検出素子に有用であり、素子のエネルギ−分解能の改善
を目的に、従来からその製造方法が検討されている。2. Description of the Related Art CdTe single crystals are useful for radiation detection elements that can operate at room temperature, and methods of manufacturing them have been studied for the purpose of improving the energy resolution of the elements.
【０００３】高エネルギ−分解能を達成するためには、
抵抗率が高いことが重要である。抵抗率が低いと放射線
検出器の信号ノイズが増大し好ましくなく、１×１０８
Ωｃｍ以上が必要である。[0003] In order to achieve high energy resolution,
It is important that the resistivity is high. If the resistivity is low, the signal noise of the radiation detector will increase, which is undesirable.
Ωcm or more is required.
【０００４】しかし、不純物無添加のＣｄＴｅ単結晶で
は、Ｃｄの空孔がアクセプタとなって、ｐ型で１００Ω
ｃｍ程度の抵抗率のものしか得られない。However, in a CdTe single crystal with no impurities added, the Cd vacancies act as acceptors, and the p-type resistance is 100Ω.
Only resistivity of about cm can be obtained.
【０００５】また、ドナ−不純物であるＣｌやＩｎを添
加することによって、Ｃｄの空孔によるアクセプタを補
償して、抵抗率を向上する方法が知られているが、Ｃｌ
を添加した場合、作製した放射線検出素子の計数率がバ
イアス電圧の印加後の時間に伴って、大きく変化すると
いう問題がある。Ｉｎ添加の場合には、このような問題
はないが、高い抵抗率のＣｄＴｅ単結晶を再現性良く製
造できないという問題があった。[0005] Furthermore, a method is known in which the resistivity is improved by adding donor impurities such as Cl or In to compensate for acceptors caused by Cd vacancies.
When adding , there is a problem that the counting rate of the fabricated radiation detection element changes greatly with time after the bias voltage is applied. In the case of adding In, there is no such problem, but there is a problem that a CdTe single crystal with high resistivity cannot be manufactured with good reproducibility.
【０００６】[0006]
【発明が解決しようとする問題点】本発明は、上記の問
題点を解決したものであって、Ｉｎ添加した高抵抗率の
ＣｄＴｅ単結晶を再現性良く製造できる方法を提供する
ものである。SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a method for manufacturing CdTe single crystals doped with In and having high resistivity with good reproducibility.
【０００７】[0007]
【問題点を解決するための手段および作用】本発明は、
Ｉｎを０．００１重量ｐｐｍ以上、１．５重量ｐｐｍ以
下の濃度となるように添加したＣｄＴｅ単結晶を、真空
中、あるいは不活性ガス中で１５０℃以上、２５０℃以
下の温度で熱処理することを特徴とするＣｄＴｅ単結晶
の製造方法であり、本発明により、放射線検出素子に適
した高抵抗率のＩｎ添加ＣｄＴｅ単結晶を再現性良く得
ることができる。[Means and effects for solving the problems] The present invention has the following features:
Heat-treating a CdTe single crystal to which In has been added at a concentration of 0.001 ppm or more and 1.5 ppm or less in a vacuum or in an inert gas at a temperature of 150°C or more and 250°C or less. According to the present invention, an In-doped CdTe single crystal with high resistivity suitable for radiation detection elements can be obtained with good reproducibility.
【０００８】本発明者は、結晶の熱履歴が抵抗率に大き
く影響すると考え、Ｉｎ濃度レベルの異なるＣｄＴｅ単
結晶を熱処理温度を変化させて熱処理し、その抵抗率を
測定する実験を行った。その実験結果を図１に示す。The inventor of the present invention believed that the thermal history of the crystal greatly affects the resistivity, and conducted an experiment in which CdTe single crystals having different In concentration levels were heat treated by varying the heat treatment temperature, and the resistivity was measured. The experimental results are shown in Figure 1.
【０００９】実験は、ＣｄＴｅ単結晶中のＩｎ濃度が０
．０５重量ｐｐｍ，０．５重量ｐｐｍ，１．９重量ｐｐ
ｍのもの及びＩｎ無添加のものの４種類のＣｄＴｅ単結
晶をウエハ−に切断し、真空中で１１０℃から３７５℃
の温度範囲で１５時間熱処理した後、抵抗率を測定した
。In the experiment, the In concentration in the CdTe single crystal was 0.
．． 05 weight ppm, 0.5 weight ppm, 1.9 weight ppm
Four types of CdTe single crystals, one with no addition of In and one with no addition of In, were cut into wafers and heated at 110°C to 375°C in vacuum.
After heat treatment at a temperature range of 15 hours, the resistivity was measured.
【００１０】図１より、Ｉｎ無添加のものは熱処理温度
に無関係に抵抗率はほぼ１×１０２Ωｃｍで変化がない
。また、Ｉｎ濃度が１．９重量ｐｐｍのものでは、熱処
理温度が高くなるに従って抵抗率が低下している。これ
らに対し、Ｉｎ濃度が０．０５重量ｐｐｍ及び０．５重
量ｐｐｍのものでは、熱処理温度２００℃付近で抵抗率
が最高値を示し、１×１０９Ωｃｍに達している。As shown in FIG. 1, the resistivity of the material without In added is approximately 1.times.10.sup.2 .OMEGA.cm and does not change regardless of the heat treatment temperature. Further, in the case where the In concentration is 1.9 ppm by weight, the resistivity decreases as the heat treatment temperature increases. On the other hand, in the cases where the In concentration is 0.05 ppm by weight and 0.5 ppm by weight, the resistivity reaches its maximum value at around the heat treatment temperature of 200° C., reaching 1×10 9 Ωcm.
【００１１】本発明における熱処理温度は、放射線検出
素子用として必要な抵抗率１×１０８Ωｃｍ以上とする
ために、１５０℃以上、２５０℃以下とされる。The heat treatment temperature in the present invention is set at 150° C. or higher and 250° C. or lower in order to obtain a resistivity of 1×10 8 Ωcm or higher, which is necessary for a radiation detection element.
【００１２】本発明におけるＣｄＴｅ単結晶へのＩｎの
添加濃度は０．００１重量ｐｐｍ以上、１．５重量ｐｐ
ｍ以下とされる。０．００１重量ｐｐｍ未満では、無添
加と同程度の結果しか得られず、１．５重量ｐｐｍを超
えると、熱処理温度２００℃付近で抵抗率が最高値を示
さなくなる。In the present invention, the concentration of In added to the CdTe single crystal is 0.001 ppm by weight or more and 1.5 ppm by weight.
m or less. If it is less than 0.001 ppm by weight, results comparable to those obtained without the addition will be obtained, and if it exceeds 1.5 ppm by weight, the resistivity will not reach its maximum value at around the heat treatment temperature of 200°C.
【００１３】本発明における熱処理雰囲気は、結晶の酸
化防止のため真空中あるいはＡｒ、窒素などの不活性ガ
ス雰囲気とされる。The heat treatment atmosphere in the present invention is a vacuum or an inert gas atmosphere such as Ar or nitrogen to prevent oxidation of the crystal.
【００１４】本発明の熱処理時間は、１時間以上とし、
好ましくは１５時間以上とされる。なお、ＣｄＴｅ単結
晶の熱処理時の形状はウエハ−でも、インゴットで行な
っても同様の効果を得ることができる。[0014] The heat treatment time of the present invention is 1 hour or more,
Preferably it is 15 hours or more. Note that the same effect can be obtained whether the CdTe single crystal is heat-treated in a wafer shape or an ingot shape.
【００１５】[0015]
【実施例】結晶中のＩｎ濃度が０．５重量ｐｐｍとなる
ようにＩｎを添加して、ＴＨＭ法でＣｄＴｅ単結晶を育
成した。EXAMPLE A CdTe single crystal was grown by the THM method by adding In so that the In concentration in the crystal was 0.5 ppm by weight.
【００１６】このＣｄＴｅ単結晶をウエハ−に切断し、
真空中で２２０℃で１５時間熱処理した後、熱処理炉内
で冷却速度１０〜５０℃／Ｈｒの範囲で室温まで冷却後
、抵抗率を測定した。抵抗率はすべて（１〜２）×１０
９Ωｃｍと一様であり、放射線検出素子に十分な抵抗率
であった。[0016] This CdTe single crystal was cut into wafers,
After heat treatment at 220°C in vacuum for 15 hours, the resistivity was measured after cooling to room temperature in a heat treatment furnace at a cooling rate of 10 to 50°C/Hr. All resistivities are (1-2) x 10
The resistivity was uniform at 9 Ωcm, which was sufficient for a radiation detection element.
【００１７】[0017]
【比較例１】実施例１で成長した単結晶を熱処理を行な
わないで抵抗率の測定を行なったところ、１×１０５〜
３×１０７Ωｃｍと大きなバラツキを示し、放射線検出
素子用には抵抗率が不足であった。[Comparative Example 1] When the resistivity of the single crystal grown in Example 1 was measured without heat treatment, it was found that the resistivity was 1×105~
It showed a large variation of 3×10 7 Ωcm, and the resistivity was insufficient for use as a radiation detection element.
【００１８】[0018]
【発明の効果】Ｉｎを０．００１重量ｐｐｍ以上、１．
５重量ｐｐｍ以下の濃度となるように添加したＣｄＴｅ
単結晶を、真空中、あるいは不活性ガス中で１５０℃以
上、２５０℃以下の温度で熱処理することにより、放射
線検出素子用に適した高抵抗率のＩｎ添加ＣｄＴｅ単結
晶を再現性良く得ることができる。Effect of the invention: In is 0.001 ppm or more by weight, 1.
CdTe added to a concentration of 5 ppm by weight or less
To obtain an In-doped CdTe single crystal with high resistivity suitable for radiation detection elements with good reproducibility by heat-treating the single crystal at a temperature of 150°C or higher and 250°C or lower in vacuum or in an inert gas. Can be done.
【図１】Ｉｎ濃度レベルの異なるＣｄＴｅ単結晶を熱処
理温度を変化させて熱処理し、その抵抗率を測定した結
果を示す図である。FIG. 1 is a diagram showing the results of heat treating CdTe single crystals with different In concentration levels at varying heat treatment temperatures and measuring their resistivities.
Claims (1)
．５重量ｐｐｍ以下の濃度となるように添加したＣｄＴ
ｅ単結晶を、真空中、あるいは不活性ガス中で１５０℃
以上、２５０℃以下の温度で熱処理することを特徴とす
るＣｄＴｅ単結晶の製造方法。Claim 1: 0.001 ppm or more by weight of In, 1
．． CdT added to a concentration of 5 ppm by weight or less
eSingle crystal at 150℃ in vacuum or inert gas.
As described above, a method for producing a CdTe single crystal is characterized in that heat treatment is performed at a temperature of 250° C. or lower.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16748491A JP2858598B2 (en) | 1991-06-13 | 1991-06-13 | Method for producing CdTe single crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16748491A JP2858598B2 (en) | 1991-06-13 | 1991-06-13 | Method for producing CdTe single crystal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04367597A true JPH04367597A (en) | 1992-12-18 |
| JP2858598B2 JP2858598B2 (en) | 1999-02-17 |
Family
ID=15850541
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16748491A Expired - Lifetime JP2858598B2 (en) | 1991-06-13 | 1991-06-13 | Method for producing CdTe single crystal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2858598B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014196213A (en) * | 2013-03-29 | 2014-10-16 | Jx日鉱日石金属株式会社 | Semiconductor wafer, radiation detection element, radiation detector and method of producing compound semiconductor single crystal |
| JP2017197413A (en) * | 2016-04-28 | 2017-11-02 | Ｊｘ金属株式会社 | Compound semiconductor substrate and manufacturing method thereof |
-
1991
- 1991-06-13 JP JP16748491A patent/JP2858598B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014196213A (en) * | 2013-03-29 | 2014-10-16 | Jx日鉱日石金属株式会社 | Semiconductor wafer, radiation detection element, radiation detector and method of producing compound semiconductor single crystal |
| JP2017197413A (en) * | 2016-04-28 | 2017-11-02 | Ｊｘ金属株式会社 | Compound semiconductor substrate and manufacturing method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2858598B2 (en) | 1999-02-17 |
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