JP2626715B2 - Etching solution for CdTe crystal - Google Patents
Etching solution for CdTe crystalInfo
- Publication number
- JP2626715B2 JP2626715B2 JP3358397A JP35839791A JP2626715B2 JP 2626715 B2 JP2626715 B2 JP 2626715B2 JP 3358397 A JP3358397 A JP 3358397A JP 35839791 A JP35839791 A JP 35839791A JP 2626715 B2 JP2626715 B2 JP 2626715B2
- Authority
- JP
- Japan
- Prior art keywords
- plane
- weight
- crystal
- etching solution
- cdte
- 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.)
- Expired - Lifetime
Links
Landscapes
- Light Receiving Elements (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
- Weting (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は、結晶評価技術に関し、
特にCdTe結晶(カドミウムとテルルの化合物半導体
結晶)の評価に利用して好適なエッチング液に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal evaluation technique,
Particularly, the present invention relates to an etching solution suitable for use in evaluating CdTe crystals (compound semiconductor crystals of cadmium and tellurium).
【0002】[0002]
【従来の技術】CdTe結晶は、赤外線検出素子のエピ
タキシャル成長用基板や太陽電池、放射線検出素子の基
板等に用いられる。これらのデバイスの特性は、基板と
なる結晶の欠陥に依存する場合が多く、結晶欠陥を表す
エッチピットを調べることにより、結晶を評価できると
ともに、デバイスの特性をも予測することができる。従
来、CdTe結晶の評価用のエッチング液としては、例
えば85重量%の乳酸と、30重量%の硝酸と、50重
量%のフッ化水素酸とを、体積比で25:(5〜1
2):(1〜6)で混合したエッチング液が提案されて
いる(特開昭63−62237号)。2. Description of the Related Art CdTe crystals are used for substrates for epitaxial growth of infrared detecting elements, solar cells, substrates of radiation detecting elements, and the like. In many cases, the characteristics of these devices depend on the defects of the crystal serving as the substrate. By examining the etch pits representing the crystal defects, the crystal can be evaluated and the characteristics of the device can be predicted. Conventionally, as an etchant for evaluating a CdTe crystal, for example, 85% by weight of lactic acid, 30% by weight of nitric acid, and 50% by weight of hydrofluoric acid have a volume ratio of 25: (5-1).
2): An etching solution mixed in (1-6) has been proposed (JP-A-63-62237).
【0003】[0003]
【発明が解決しようとする課題】しかしながら、上記乳
酸−硝酸−フッ化水素酸系のエッチング液にあっては、
(111)B面にはエッチピットが現われるものの、
(111)A面や(100)面、(110)面にはエッ
チピットが現われにくいという不都合がある。また、
(111)B面に現われるエッチピットも、顕微鏡を用
いて200〜500倍に拡大しないと観察できない。こ
のように高い倍率で顕微鏡観察する場合、視野の移動に
時間がかかるとともに、ウェーハ1枚当たりの観測点の
数が多くなり、評価に要する時間が長くなってしまうと
いう不都合がある。特に近年、結晶は歩留まりを高くす
るため大口径化される傾向があるので、観察の倍率が高
いとますます評価に要する時間が長くなってしまう。However, in the above-mentioned lactic acid-nitric acid-hydrofluoric acid type etching solution,
Although etch pits appear on the (111) B surface,
The (111) A plane, the (100) plane, and the (110) plane have a disadvantage that etch pits hardly appear. Also,
Etch pits appearing on the (111) B surface cannot be observed unless the magnification is 200 to 500 times using a microscope. When observing with a microscope at such a high magnification, there is a disadvantage that it takes time to move the visual field, and the number of observation points per wafer increases, which increases the time required for evaluation. In particular, in recent years, crystals tend to have a large diameter in order to increase the yield, so that the higher the magnification of observation, the longer the time required for evaluation.
【0004】この発明は上記のような問題点に着目して
なされたもので、その目的とするところは、(111)
B面以外の結晶面にもエッチピットが現われるととも
に、低倍率でそのエッチピットを観察することができる
ようなCdTe結晶評価用のエッチング液を提供するこ
とにある。The present invention has been made in view of the above-mentioned problems.
An object of the present invention is to provide an etchant for evaluating a CdTe crystal in which etch pits appear on a crystal plane other than the B-plane and the etch pits can be observed at a low magnification.
【0005】[0005]
【課題を解決するための手段】上記目的を達成するた
め、この発明は、85重量%の乳酸と、30重量%の過
酸化水素と、36重量%の塩酸とを、体積比で25:
(5〜25):(1〜12)で混合したことを特徴とす
るCdTe結晶用エッチング液を提案するものである。
この発明の前記ならびにそのほかの目的と新規な特徴に
ついては、本明細書の記述および添附図面から明らかに
なるであろう。In order to achieve the above-mentioned object, the present invention relates to a method for producing 85% by weight of lactic acid, 30% by weight of hydrogen peroxide and 36% by weight of hydrochloric acid in a volume ratio of 25:
(5-25): An etching solution for CdTe crystal characterized by being mixed in (1-12).
The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
【0006】[0006]
【作用】上記組成のエッチング液を用いてCdTe結晶
をエッチングすると、(111)B面および(111)
A面に低倍率で観察できる三角形のエッチピットが出現
するとともに、(100)面にはへき開方向と一致する
低倍率で観察可能な長方形のエッチピットが出現するた
め、各結晶面の評価を迅速に行なえるとともに、エッチ
ピットの方向を見て面方位の決定ができるようになる。
また、高倍率を必要とはするが、(110)面にもエッ
チピットが出現するようになるため、結晶の評価をより
厳密に行なうことができる。さらに、上記組成のエッチ
ング液によれば、メサエッチングおよび逆メサエッチン
グを行なえるため、X線を使用せずに面方位を判断でき
るとともに、デバイス作成時のエッチャントとしても利
用することができる。When a CdTe crystal is etched using an etching solution having the above composition, the (111) B plane and the (111) B
A triangular etch pit that can be observed at a low magnification appears on the A-plane, and a rectangular etch pit that can be observed at a low magnification coincides with the cleavage direction appears on the (100) plane. In addition, the orientation of the plane can be determined by looking at the direction of the etch pit.
Although high magnification is required, etch pits also appear on the (110) plane, so that crystal evaluation can be performed more strictly. Further, according to the etchant having the above composition, mesa etching and reverse mesa etching can be performed, so that the plane orientation can be determined without using X-rays and can be used as an etchant at the time of device fabrication.
【0007】[0007]
【実施例】85重量%の乳酸と、30重量%の過酸化水
素と、36重量%の塩酸とを、体積比で25:(5〜2
5):(1〜12)の割合で混合した混合液を作る。こ
の混合液中に、表面の加工変質層を除去したCdTe単
結晶を浸漬し、混合液を撹拌する。約2分後に、上記C
dTe単結晶を混合液より取り出し、水洗した後に乾燥
させる。上記方法により、(111)B面と(100)
面を持つCdTe単結晶をエッチングしたところ、(1
11)B面には図1に示すようなエッチピットが、また
(100)面には図2に示すようなエッチピットが出現
した。図1において三角形を成している部分と、図2に
おいて長方形を成している部分がそれぞれエッチピット
である。EXAMPLE 85% by weight of lactic acid, 30% by weight of hydrogen peroxide and 36% by weight of hydrochloric acid were mixed in a volume ratio of 25: (5-2).
5): A mixed solution mixed at a ratio of (1 to 12) is prepared. The CdTe single crystal from which the surface deteriorated layer has been removed is immersed in the mixture, and the mixture is stirred. After about 2 minutes, the above C
The dTe single crystal is taken out of the mixed solution, washed with water and dried. By the above method, the (111) B surface and the (100)
When a CdTe single crystal having a plane was etched, (1
11) Etch pits as shown in FIG. 1 appeared on plane B, and etch pits as shown in FIG. 2 appeared on (100) plane. A portion forming a triangle in FIG. 1 and a portion forming a rectangle in FIG. 2 are etch pits.
【0008】さらに、上記組成の混合液の体積比を種々
変えてエッチング実験を行なったところ、体積比が2
5:(5〜25):(1〜12)の範囲で観察可能なエ
ッチピットが出現した。しかるに、混合液中の塩酸の割
合が上記範囲よりも多いとエッチピットの判別ができな
かった。上記組成の混合液によるエッチングのメカニズ
ムは、混合液中の過酸化水素で結晶表面を酸化させ、こ
の生成酸化物を塩酸で除去するというものであるので、
塩酸の割合が上記範囲よりも多いと欠陥のないところま
でエッチングされてしまい、エッチピットが明瞭にでな
くなるためである。また、混合液中の過酸化水素の割合
が上記範囲よりも多いと、結晶表面が黒色化してしまっ
た。過酸化水素による酸化力が強すぎて厚い酸化膜が形
成され、塩酸による除去量が不足したためである。一
方、混合液中の過酸化水素の割合が上記範囲よりも少な
いと酸化膜が形成されず、塩酸の割合が上記範囲よりも
少ないとエッチング力が弱くて、いずれもエッチピット
が出現しない。Further, when an etching experiment was conducted by changing the volume ratio of the mixed solution having the above composition, the volume ratio was found to be 2%.
5: (5 to 25): Observable etch pits appeared in the range of (1 to 12). However, if the ratio of hydrochloric acid in the mixture was higher than the above range, the etch pit could not be determined. The mechanism of etching with the mixture of the above composition is that the crystal surface is oxidized with hydrogen peroxide in the mixture and the generated oxide is removed with hydrochloric acid.
If the ratio of hydrochloric acid is more than the above range, the etching is performed to the point where there is no defect, and the etch pits are not clear. On the other hand, if the proportion of hydrogen peroxide in the mixture was higher than the above range, the crystal surface was blackened. This is because the oxidizing power of hydrogen peroxide is too strong, a thick oxide film is formed, and the removal amount by hydrochloric acid is insufficient. On the other hand, if the proportion of hydrogen peroxide in the mixed solution is smaller than the above range, no oxide film is formed, and if the proportion of hydrochloric acid is smaller than the above range, the etching power is weak, and neither etch pit appears.
【0009】なお、上記実施例では、85重量%の乳酸
と、30重量%の過酸化水素と、36重量%の塩酸とを
混合してエッチング液としたが、他の濃度の乳酸、過酸
化水素、塩酸を混合してエッチング液としても良いこと
は勿論である。その場合、使用可能な混合液の体積比
は、濃度100%に換算して21.25:(1.5〜
7.5):(0.36〜4.32)の範囲を基準とする
のがよい。例えば、30重量%の過酸化水素の代わり
に、50重量%の過酸化水素を用いる場合(乳酸は85
重量、塩酸は36重量%)には、体積比で25:(5〜
25):(1〜12)の範囲で混合したものをエッチン
グ液とすれば良い。In the above embodiment, 85% by weight of lactic acid, 30% by weight of hydrogen peroxide, and 36% by weight of hydrochloric acid were mixed to form an etching solution. However, other concentrations of lactic acid and peroxide were used. Of course, hydrogen and hydrochloric acid may be mixed to form an etching solution. In that case, the volume ratio of the usable liquid mixture is 21.25: (1.5 to
7.5): The range of (0.36 to 4.32) is preferably used as a reference. For example, when 50% by weight of hydrogen peroxide is used instead of 30% by weight of hydrogen peroxide (lactic acid is 85%).
Weight, hydrochloric acid is 36% by weight), the volume ratio is 25: (5-
25): What is mixed in the range of (1 to 12) may be used as an etching solution.
【0010】[0010]
【発明の効果】以上説明したように、この発明は、85
重量%の乳酸と、30重量%の過酸化水素と、36重量
%の塩酸とを、体積比で25:(5〜25):(1〜1
2)で混合したものをCdTe結晶のエッチング液とし
たので、この組成のエッチング液を用いてCdTe結晶
をエッチングすると、(111)B面および(111)
A面に低倍率で観察できる三角形のエッチピットが出現
するとともに、(100)面にはへき開方向と一致する
低倍率で観察可能な長方形のエッチピットが出現するた
め、各結晶面の評価を迅速に行なえるとともに、エッチ
ピットの方向を見て面方位の決定ができるようになる。
また、高倍率を必要とはするが(110)面にもエッチ
ピットが出現するため、結晶の評価をより厳密に行なう
ことができる。さらに、上記組成のエッチング液によれ
ば、メサエッチングおよび逆メサエッチングを行なえる
ため、X線を使用せずに面方位を判断できるとともに、
デバイス作成時のエッチャントとしても利用することが
できるという効果がある。As described above, the present invention has a
Weight% lactic acid, 30 weight% hydrogen peroxide and 36 weight% hydrochloric acid in a volume ratio of 25: (5-25) :( 1-1
Since the mixture obtained in 2) was used as an etchant for a CdTe crystal, etching the CdTe crystal using an etchant of this composition yielded a (111) B plane and a (111) B plane.
A triangular etch pit that can be observed at a low magnification appears on the A-plane, and a rectangular etch pit that can be observed at a low magnification coincides with the cleavage direction appears on the (100) plane. In addition, the orientation of the plane can be determined by looking at the direction of the etch pit.
Further, although high magnification is required, since etch pits also appear on the (110) plane, crystal evaluation can be performed more strictly. Further, according to the etching solution having the above composition, mesa etching and reverse mesa etching can be performed, so that the plane orientation can be determined without using X-rays.
There is an effect that it can be used also as an etchant at the time of device creation.
【図面の簡単な説明】[Brief description of the drawings]
【図1】本発明にかかるエッチング液を用いてCdTe
単結晶をエッチングしたときに(111)B面に出現す
るエッチピットを示す図である。FIG. 1 shows CdTe using an etching solution according to the present invention.
It is a figure which shows the etch pit which appears on a (111) B plane when a single crystal is etched.
【図2】本発明にかかるエッチング液を用いてCdTe
単結晶をエッチングしたときに(100)面に出現する
エッチピットを示す図である。FIG. 2 shows CdTe using an etching solution according to the present invention.
It is a figure which shows the etch pit which appears on a (100) plane when a single crystal is etched.
Claims (1)
化水素と、36重量%の塩酸とを、体積比で25:(5
〜25):(1〜12)で混合したことを特徴とするC
dTe結晶用エッチング液。1. A mixture of 85% by weight of lactic acid, 30% by weight of hydrogen peroxide and 36% by weight of hydrochloric acid in a volume ratio of 25: (5
~ 25): C characterized by being mixed in (1-12)
Etching solution for dTe crystal.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3358397A JP2626715B2 (en) | 1991-12-27 | 1991-12-27 | Etching solution for CdTe crystal |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3358397A JP2626715B2 (en) | 1991-12-27 | 1991-12-27 | Etching solution for CdTe crystal |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH05182950A JPH05182950A (en) | 1993-07-23 |
JP2626715B2 true JP2626715B2 (en) | 1997-07-02 |
Family
ID=18459083
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3358397A Expired - Lifetime JP2626715B2 (en) | 1991-12-27 | 1991-12-27 | Etching solution for CdTe crystal |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2626715B2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5228948B2 (en) * | 2009-01-30 | 2013-07-03 | 株式会社大真空 | Piezoelectric vibration device |
CN110061094A (en) * | 2019-03-14 | 2019-07-26 | 中山瑞科新能源有限公司 | A kind of cadmium telluride thin-film battery surface clean pretreating process |
-
1991
- 1991-12-27 JP JP3358397A patent/JP2626715B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPH05182950A (en) | 1993-07-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Tarui et al. | Preferential etching and etched profile of GaAs | |
KR100930294B1 (en) | Chromium-free etching solution for Si-substrate and SiSie-substrate, a method for indicating defects using the etching solution and a process for treating Si-substrate and SiSie-substrate using the etching solution | |
EP1852905B1 (en) | Preferential etching method and silicon single crystal substrate | |
EP0473150A2 (en) | Method for fabricating a semiconductor device including a step for cleaning a semiconductor substrate | |
Mehta et al. | Controlled etching behavior of O-polar and Zn-polar ZnO single crystals | |
JPS63280424A (en) | Method of forming recess in silicon substrate by etching | |
US5067989A (en) | Single crystal silicon | |
US3600241A (en) | Method of fabricating semiconductor devices by diffusion | |
JP2626715B2 (en) | Etching solution for CdTe crystal | |
JP2894717B2 (en) | Low surface tension sulfuric acid composition | |
JPH1167742A (en) | Etching solution for semiconductor substrate and etching | |
JPH07263429A (en) | Selective etching liquid | |
JP2626716B2 (en) | Etching solution for CdTe crystal | |
US4588446A (en) | Method for producing graded band gap mercury cadmium telluride | |
US4997522A (en) | Wet chemical etchant and method for etching high temperature superconductive films | |
Bagai et al. | Preferential etchant for revealing crystallographic defects on (111) Te surface of CdTe crystals | |
JP4711167B2 (en) | Manufacturing method of silicon epitaxial wafer | |
JP2004235350A (en) | Crystal defect evaluating method of soi wafer and etching liquid | |
RU2619423C1 (en) | Composition of selective thinner for tellurid of cadmium-mercury | |
Bagai et al. | Nature of the crystallographic defects on the (111) Te surface of CdTe delineated by preferential etching | |
JP2848176B2 (en) | Semiconductor single crystal defect detection method | |
Possner et al. | Organic Peracid Etches: a new class of chromium free etch solutions for the delineation of defects in different semiconducting materials | |
SU1660407A1 (en) | Niobatic barium-strontium pickling agent | |
JPS6362237A (en) | Etching liquid for cdte crystal | |
JP3201793B2 (en) | Processing method of Si substrate |