JPS6233310B2 - - Google Patents
Info
- Publication number
- JPS6233310B2 JPS6233310B2 JP18084681A JP18084681A JPS6233310B2 JP S6233310 B2 JPS6233310 B2 JP S6233310B2 JP 18084681 A JP18084681 A JP 18084681A JP 18084681 A JP18084681 A JP 18084681A JP S6233310 B2 JPS6233310 B2 JP S6233310B2
- Authority
- JP
- Japan
- Prior art keywords
- etching
- film
- solution
- alloy
- iodine
- 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
Links
- 238000005530 etching Methods 0.000 claims description 30
- 229910000927 Ge alloy Inorganic materials 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 10
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 6
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical compound [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 claims description 6
- BYDQGSVXQDOSJJ-UHFFFAOYSA-N [Ge].[Au] Chemical compound [Ge].[Au] BYDQGSVXQDOSJJ-UHFFFAOYSA-N 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 229910001868 water Inorganic materials 0.000 claims description 3
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 claims description 2
- 239000000758 substrate Substances 0.000 description 11
- 229910001020 Au alloy Inorganic materials 0.000 description 8
- 229910052740 iodine Inorganic materials 0.000 description 6
- 239000011630 iodine Substances 0.000 description 6
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 5
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229920002120 photoresistant polymer Polymers 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- MDPILPRLPQYEEN-UHFFFAOYSA-N aluminium arsenide Chemical compound [As]#[Al] MDPILPRLPQYEEN-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- HZXMRANICFIONG-UHFFFAOYSA-N gallium phosphide Chemical compound [Ga]#P HZXMRANICFIONG-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- DKNPRRRKHAEUMW-UHFFFAOYSA-N Iodine aqueous Chemical compound [K+].I[I-]I DKNPRRRKHAEUMW-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002496 iodine Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/10—Etching compositions
- C23F1/14—Aqueous compositions
Description
【発明の詳細な説明】
本発明は−族化合物半導体の電極のエツチ
ングに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to etching of electrodes of -group compound semiconductors.
金−ゲルマニウム（Au／Ge）合金は、燐化ガ
リウム（GaP）、砒化ガリウム（GaAs）等の−
族化合物半導体のｎ形に対して良好なオーミツ
ク性を有するため、現在発光ダイオードや半導体
レーザ等のｎ側電極として広く用いられている。 Gold-germanium (Au/Ge) alloys include gallium phosphide (GaP), gallium arsenide (GaAs), etc.
Since it has good ohmic properties with respect to n-type group compound semiconductors, it is currently widely used as n-side electrodes in light-emitting diodes, semiconductor lasers, and the like.
このAu／Ge合金を選択的にエツチングするた
めには、第１図に示すように通常ホトレジスト膜
１をマスクとし、同マスクの開孔部を通じて同位
置のAu／Ge合金膜２をエツチングで除去するの
に、ヨウ素、ヨウ化カリからなるいわゆるヨード
エツチ液が用いられている。しかしながら、この
ヨードエツチ液で実際にエツチングを行うとエツ
チ時間が長くなりサイドエツチが起りパターンく
ずれ等を引き起し精度のよいエツチングが困難で
あるという問題が生じてくる。これはAu／Ge合
金膜２の付着時に合金組成物中のゲルマニウムが
基板４と反応し膜２との界面に変成層３が形成さ
れ、基板４との界面近くで付着合金膜のエツチン
グ速度が遅くなることに起因している。 In order to selectively etch this Au/Ge alloy, normally a photoresist film 1 is used as a mask as shown in Figure 1, and the Au/Ge alloy film 2 at the same position is removed by etching through the opening of the mask. For this purpose, a so-called iodine etch solution consisting of iodine and potassium iodide is used. However, when etching is actually performed using this iodine etching solution, the etching time becomes long, side etching occurs, causing pattern distortion, etc., and the problem arises that accurate etching is difficult. This is because when the Au/Ge alloy film 2 is deposited, germanium in the alloy composition reacts with the substrate 4, forming a metamorphic layer 3 at the interface with the film 2, and the etching rate of the deposited alloy film decreases near the interface with the substrate 4. This is due to the delay.
このように、Au／Ge合金の電極形成用膜を通
常のヨードエツチ液で精度よくエツチすることは
極めて難しく、かかるエツチング工程でも、しば
しば、上記変成層３が残る。このためこの部分で
の光の吸収が起り、発光出力が大幅に低下する等
の悪影響を与える。 As described above, it is extremely difficult to accurately etch the Au/Ge alloy electrode forming film using a normal iodine etching solution, and even in such an etching process, the metamorphic layer 3 often remains. As a result, light is absorbed in this portion, resulting in adverse effects such as a significant reduction in light emission output.
本発明はこれらの難点を解消することを目的と
してなされたものであり、金−ゲルマニウム合金
を選択的に容易に精度よくエツチングするととも
に、前述の変成層をも除去出来るエツチング法を
提供するものである。 The present invention has been made with the aim of solving these difficulties, and provides an etching method that can selectively and easily etch gold-germanium alloys with high accuracy, and can also remove the metamorphic layer described above. be.
以下、本発明について実施例を参考にして詳細
に述べる。ここではｎ形基板としてGaAsを用い
た場合について述べるが、本発明は他の−族
化合物半導体、例えば燐化ガリウム（GaP）、砒
化ガリウム・アルミニウム（GaAlAs）等にも適
用出来る。 Hereinafter, the present invention will be described in detail with reference to Examples. Although the case where GaAs is used as the n-type substrate will be described here, the present invention can also be applied to other - group compound semiconductors such as gallium phosphide (GaP), gallium aluminum arsenide (GaAlAs), etc.
第２図は本発明の実施例のフローチヤートで、
主要構造を断面図で示したものである。第２図ａ
に示すように、ｎ形基板４として1.0〜２×1018
cm-3のキヤリア濃度を有するGaAsを用い、表面
を鏡面研磨した後、硫酸：過酸化水素水：水（容
積比８：１：１）でエツチし、真空蒸着法にて、
重量比Au：Ge＝100：2.5のAu／Ge合金膜２を付
着する。蒸着条件は基板温度250℃、真空度1.5×
10-6Torr、膜厚は1.5μである。この状態でｎ形
基板表面には変成層３が生成されている。 FIG. 2 is a flowchart of an embodiment of the present invention.
This is a cross-sectional view of the main structure. Figure 2a
As shown in , the n-type substrate 4 is 1.0 to 2×10 18
Using GaAs with a carrier concentration of cm -3 , the surface was mirror-polished, etched with sulfuric acid: hydrogen peroxide: water (volume ratio 8:1:1), and then vacuum evaporated.
An Au/Ge alloy film 2 with a weight ratio of Au:Ge=100:2.5 is deposited. Vapor deposition conditions are substrate temperature 250℃, vacuum degree 1.5×
10 -6 Torr, film thickness 1.5μ. In this state, a metamorphic layer 3 is generated on the surface of the n-type substrate.
次にホトレジスト膜１をマスクとして、140μ
φの円形パターンの選択エツチングを行う。エツ
チング液は第１溶液としてヨウ素、ヨウ化カリ、
水を所定の混合比例えば52ｇ、100ｇ、１で形
成したヨードエツチ液を用い、第２溶液として過
酸化水素水（31％容積比）を用意する。まず、最
初に第１溶液を用いて室温でエツチングする。
Au／Ge膜２は、本来、上記第１溶液でエツチさ
れる筈であるが、膜によつては全くエツチされな
い場合がある。この傾向はAu／Ge合金中のGeの
組成が高くなるほどよくあらわれ、また蒸着時の
形成条件等にも関係しており、イオンマイクロア
ナライザーで解析すると、Au／Ge膜表面にGeの
薄い層が形成されているのが確認された。そこ
で、第２溶液を用いて室温でこのGeをエツチン
グ除去する。この第２溶液ではAu／Ge膜自体を
エツチすることは出来ないので、表面のGe層を
除去後は再び第１溶液に侵す。Au／Ge膜は約
200Å／分の速度でスムーズにエツチングされは
じめるが、基板と膜の界面に近ずくほど、そのエ
ツチング速度が遅くなる。 Next, using photoresist film 1 as a mask,
Selective etching of a circular pattern of φ is performed. The etching solution contains iodine, potassium iodide, and
Using an iodine etch solution containing water in a predetermined mixing ratio of 52 g, 100 g, and 1, for example, a hydrogen peroxide solution (31% volume ratio) is prepared as a second solution. First, etching is performed at room temperature using the first solution.
The Au/Ge film 2 is originally supposed to be etched with the first solution, but depending on the film, it may not be etched at all. This tendency appears more frequently as the Ge composition in the Au/Ge alloy increases, and is also related to the formation conditions during vapor deposition. Analysis with an ion microanalyzer reveals that a thin layer of Ge is formed on the surface of the Au/Ge film. It was confirmed that it was formed. Therefore, this Ge is removed by etching at room temperature using a second solution. Since the Au/Ge film itself cannot be etched with this second solution, after removing the Ge layer on the surface, the first solution is used again. Au/Ge film is approx.
Etching begins smoothly at a rate of 200 Å/min, but the etching rate slows down as it approaches the interface between the substrate and film.
解析によると、界面近くの膜中にもGeが高濃
度に存在している。そこで、再び第２溶液に侵し
このGe高濃度層を溶解し、次に再び第１溶液で
エツチングする。 According to the analysis, there is a high concentration of Ge in the film near the interface. Therefore, the layer is again immersed in the second solution to dissolve this Ge-rich layer, and then etched again with the first solution.
このように、第１、第２溶液を用いて、Au／
Ge膜のエツチングを交互に行うことにより、第
２図ｂのようになる。この状態では、まだ変成層
３が残つているため、第２溶液を用い温度60℃で
除去を開始する。変成層３には、ガリウム
（Ga）、Geが主に含まれており、室温ではエツチ
ング速度が低いため、60℃に加熱エツチングする
方が望ましい。通常、１分以内で第２図ｃのよう
に変成層３は完全に除去され、除去後の基板表面
５も鏡面を保つている。エツチング完了後、本発
明のエツチング法と通常のヨードエツチング法に
よるパターン精度を比較すると、通常のエツチン
グ法では５μ程度のオーバーエツチが観察された
が、本発明では1.0μ以内におさまつていた。 In this way, using the first and second solutions, Au/
By alternately etching the Ge film, the result is as shown in FIG. 2b. In this state, since the metamorphic layer 3 still remains, removal is started using the second solution at a temperature of 60°C. The metamorphic layer 3 mainly contains gallium (Ga) and Ge, and since the etching rate is low at room temperature, it is preferable to perform etching by heating to 60°C. Normally, the metamorphic layer 3 is completely removed within one minute as shown in FIG. 2c, and the substrate surface 5 after removal also maintains a mirror surface. After the etching was completed, we compared the pattern accuracy between the etching method of the present invention and the conventional iodine etching method, and found that overetching of about 5 μm was observed with the conventional etching method, but it was within 1.0 μm with the present invention. .
以上のように、本発明のエツチング法はヨード
エツチ液からなる第１溶液と過酸化水素水からな
る第２溶液を用いて交互にエツチングを行うこと
により、Au／Ge合金膜のエツチを精度よくエツ
チすることを可能ならしめ、かつ上記合金膜形成
時に基板表面に発生する変成層をも確実に除去出
来るものである。 As described above, the etching method of the present invention etches the Au/Ge alloy film with high accuracy by performing etching alternately using a first solution consisting of an iodine etchant and a second solution consisting of a hydrogen peroxide solution. In addition, the metamorphic layer generated on the substrate surface during the formation of the alloy film can also be reliably removed.
第１図は通常の金−ゲルマニウム合金のエツチ
ング法を説明するための断面図、第２図ａ〜ｃは
本発明の一実施例にかかる金−ゲルマニウム合金
のエツチング法の工程断面図。
１……ホトレジスト膜、２……Au／Ge合金
膜、３……変成層、４……ｎ形GaAs基板、５…
…変成層除去後の基板表面。
FIG. 1 is a cross-sectional view for explaining a conventional gold-germanium alloy etching method, and FIGS. 2 a to 2 c are process cross-sectional views of a gold-germanium alloy etching method according to an embodiment of the present invention. 1... Photoresist film, 2... Au/Ge alloy film, 3... Metamorphic layer, 4... N-type GaAs substrate, 5...
...Substrate surface after metamorphic layer removal.
Claims (1)
酸化水素水を含む第２溶液とを用いて、交互にエ
ツチングを行うことを特徴とする金−ゲルマニウ
ム合金膜のエツチング方法。1. A method for etching a gold-germanium alloy film, characterized in that etching is performed alternately using a first solution containing iodine, potassium iodide, and water and a second solution containing hydrogen peroxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18084681A JPS5881973A (en) | 1981-11-11 | 1981-11-11 | Method for etching gold-germanium alloy film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18084681A JPS5881973A (en) | 1981-11-11 | 1981-11-11 | Method for etching gold-germanium alloy film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5881973A JPS5881973A (en) | 1983-05-17 |
| JPS6233310B2 true JPS6233310B2 (en) | 1987-07-20 |
Family
ID=16090375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18084681A Granted JPS5881973A (en) | 1981-11-11 | 1981-11-11 | Method for etching gold-germanium alloy film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5881973A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0866209A (en) * | 1994-08-16 | 1996-03-12 | Aucera Technol Corp | Structure of watch strap |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4654116A (en) * | 1984-11-09 | 1987-03-31 | American Electronic Laboratories, Inc. | Method for producing high resolution etched circuit patterns from clad laminates |
| TW200823318A (en) * | 2006-08-28 | 2008-06-01 | Mitsubishi Chem Corp | Etchant and etching method |
-
1981
- 1981-11-11 JP JP18084681A patent/JPS5881973A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0866209A (en) * | 1994-08-16 | 1996-03-12 | Aucera Technol Corp | Structure of watch strap |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5881973A (en) | 1983-05-17 |
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