JPS6150363A - Ohmic electrode - Google Patents
Ohmic electrodeInfo
- Publication number
- JPS6150363A JPS6150363A JP17194384A JP17194384A JPS6150363A JP S6150363 A JPS6150363 A JP S6150363A JP 17194384 A JP17194384 A JP 17194384A JP 17194384 A JP17194384 A JP 17194384A JP S6150363 A JPS6150363 A JP S6150363A
- Authority
- JP
- Japan
- Prior art keywords
- layer
- metal layer
- electrode
- type
- ingaasp
- 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
- 229910052751 metal Inorganic materials 0.000 claims abstract description 33
- 239000002184 metal Substances 0.000 claims abstract description 33
- 239000000758 substrate Substances 0.000 claims abstract description 24
- 239000004065 semiconductor Substances 0.000 claims abstract description 22
- 150000001875 compounds Chemical class 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 12
- 239000012535 impurity Substances 0.000 claims abstract description 11
- 230000004888 barrier function Effects 0.000 claims abstract description 8
- 238000009792 diffusion process Methods 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000000956 alloy Substances 0.000 abstract description 6
- 229910045601 alloy Inorganic materials 0.000 abstract description 6
- 238000000034 method Methods 0.000 abstract description 5
- 238000007669 thermal treatment Methods 0.000 abstract 3
- 239000010410 layer Substances 0.000 description 38
- 239000012808 vapor phase Substances 0.000 description 6
- 230000006866 deterioration Effects 0.000 description 5
- 230000008021 deposition Effects 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 3
- 238000007740 vapor deposition Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 210000004709 eyebrow Anatomy 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 210000003097 mucus Anatomy 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229910052711 selenium Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/45—Ohmic electrodes
- H01L29/452—Ohmic electrodes on AIII-BV compounds
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Ceramic Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Electrodes Of Semiconductors (AREA)
- Semiconductor Lasers (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は化合物半導体基板上に形成されたオーミック電
極に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ohmic electrode formed on a compound semiconductor substrate.
従来例の構成とその問題点
従来、ｐ型１ｎＰもしくけｐ型ｒｎＧのムｓＰ基板に対
して、コンタクト抵抗の低いオーミック電極を得る方法
としては、合金化電極を用いるものが多かった。これは
、主にムＵを電極母材として、これにＺｎ、Ｂθ等のｐ
型不純物金属を１０％程度含有させた金属層を基板上に
蒸着した後、熱処理を施して合金化反応を生じさせるも
のである。この合金化反応によって基板のＩｎ、Ｐ等と
電極母材のムＵが相互拡散をし、ムｕ３Ｉｎ、ムｕ２Ｐ
５等よりなる合金層が形成される。この合金層およυ・
その直下の基板結晶層中に多（の不純物金属原子が含ま
れているので、電極と基板間のフンタクト抵抗は低くな
る。このような合金化電極を半導体レーザに適用した場
合の断面図を第１図に示す。第１図において、電極母材
のＡｕ層１とｐ型ＩｎＧ＆ＡｇＰ層２の界面に合金層３
が存在している。しかし、半導体レーザの電極として、
このような合金化電極を用いると動作中にＡｕがさらに
基板結晶中を拡散していき、やがてはｐ型ＩｎＰ閉込め
層４を突き抜けてｒｎＧａＡｓＰ活性層６に達する。Ａ
ｕが活性層５にまで達すると半導体レーザは急速に劣化
をする。ここで、本発明との直接的な関係はないが、５
ｉｎ２膜６け電極ストライブを形成するだめのもので、
れ型１ｎＰ層７、ｐ型ＩｎＰ層８け埋込み層であり、ｎ
型ＩｎＰ基板９上にはムｕ−３ｎ電極１゜が形成されて
いる。このような人Ｕの侵入による特性の劣化は、半導
体レーザに限らず多くの化合物半導体デバイスにおいて
観測されるものであムこのような特性の劣化を防ぐため
に用いられてきた第２の従来例さしては、ムＵと基板の
間に相互拡散を防止するバリア金属を挿入する方法があ
る。バリア金属としてはＣｒ、Ｔｉ等が用いられる。Conventional Structures and Problems Conventionally, alloyed electrodes have often been used to obtain ohmic electrodes with low contact resistance for p-type 1nP or p-type rnG musP substrates. This is mainly done by using MuU as the electrode base material, and adding P such as Zn and Bθ to it.
After a metal layer containing about 10% of type impurity metal is deposited on a substrate, heat treatment is performed to cause an alloying reaction. Through this alloying reaction, In, P, etc. of the substrate and MuU of the electrode base material interdiffuse, and Mu3In and Mu2P
An alloy layer consisting of 5, etc. is formed. This alloy layer and υ・
Since a large number of impurity metal atoms are contained in the substrate crystal layer immediately below, the direct resistance between the electrode and the substrate is low.The cross-sectional view when such an alloyed electrode is applied to a semiconductor laser is shown in Fig. 1. In FIG. 1, an alloy layer 3 is formed at the interface between the Au layer 1 of the electrode base material and the p-type InG&AgP layer 2.
exists. However, as an electrode for a semiconductor laser,
When such an alloyed electrode is used, Au further diffuses into the substrate crystal during operation, eventually penetrating the p-type InP confinement layer 4 and reaching the rnGaAsP active layer 6. A
When u reaches the active layer 5, the semiconductor laser rapidly deteriorates. Here, although there is no direct relationship with the present invention, 5
This is a useless material for forming 6 in2 film electrode stripes.
1 nP layer 7, p type InP layer 8 buried layer, n
A mu-U-3n electrode 1° is formed on the InP type substrate 9. Such deterioration of characteristics due to the intrusion of a person U is observed not only in semiconductor lasers but also in many compound semiconductor devices.The second conventional example that has been used to prevent such deterioration of characteristics is There is a method of inserting a barrier metal between the mu and the substrate to prevent mutual diffusion. Cr, Ti, etc. are used as the barrier metal.
このような非合金化電極において汀、ムＵの侵入による
特性の劣化は生しないが、コンタクト抵抗が合金化電極
に比へて高（なるという欠点を有している。さらに、コ
ンタクト抵抗を丁けるためには、電極蒸着前にｐ型不純
物を気相拡散してあらかじめ基板の表面不純物濃度を高
くしておくことが不可欠であり、この気相拡散を必ずし
も必要としない合金化電極に比へて工程が複雑になる。Although such non-alloyed electrodes do not suffer from deterioration of their properties due to the intrusion of slag and silica, they have the disadvantage that their contact resistance is higher than that of alloyed electrodes. In order to achieve this, it is essential to increase the surface impurity concentration of the substrate by vapor-phase diffusion of p-type impurities before electrode deposition, which is compared to alloyed electrodes that do not necessarily require vapor-phase diffusion. The process becomes complicated.
発明の目的
本発明は上記従来の欠点を改善するもので、電１
極蒸着前。気相ヶ散エヮを必要おオず、ヵ、
９３゜タクト抵抗の低い非合金化オーミック電極の構成
法を提供するものである。OBJECTS OF THE INVENTION The present invention aims to improve the above-mentioned conventional drawbacks, and
Before polar deposition. It is necessary to dissipate the vapor phase.
A method of constructing an unalloyed ohmic electrode with low 93° tact resistance is provided.
発明の構成
本発明のオーミック電極は、化合物半導体よりなる基板
上に前記化合物半導体に対してｐ型もしくｉｎ型の不純
物となる金属よりなる第１の金属層と、前記化合物半導
体と電極母材の相互拡散を防止するバリア金属よりなる
第２の金属層と、前記電極母材よりなる第３の金属層を
順次積層し、熱処理を施したものである。Structure of the Invention The ohmic electrode of the present invention comprises, on a substrate made of a compound semiconductor, a first metal layer made of a metal serving as a p-type or in-type impurity with respect to the compound semiconductor, the compound semiconductor and an electrode base material. A second metal layer made of a barrier metal that prevents interdiffusion of the metal and a third metal layer made of the electrode base material are sequentially laminated and subjected to heat treatment.
実施例の説明
以下、本発明の具体的な実施例を図面を用いて説明する
。第２図は本発明を埋込み構造半導体レーザに適用した
場合の断面図である。半導体レーザ基板の表面層１１は
波長に換算した組成が１６１ｐｍのＩｎＧａＡｓＰ層（
キャリア密度２ ｙ １０ ｃｍ ）である。また、
５１０２膜１２け電極ストライプ構造を形成するために
設けられている。この半導体レーザ基板に対して、不純
物金属としてのＺｎ層１３、バリア金属としてのｃｒ層
１４、電極母材としてのムＵ層１６を順次蒸着し、熱処
理を施す。DESCRIPTION OF EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a cross-sectional view when the present invention is applied to a buried structure semiconductor laser. The surface layer 11 of the semiconductor laser substrate is an InGaAsP layer (with a wavelength-converted composition of 161 pm).
The carrier density is 2 y 10 cm). Also,
Twelve 5102 films are provided to form an electrode stripe structure. A Zn layer 13 as an impurity metal, a Cr layer 14 as a barrier metal, and a MuU layer 16 as an electrode base material are sequentially deposited on this semiconductor laser substrate, and then heat treated.
この蒸着は、例えば各層の膜厚をそれぞれ１ｏｏｉ、１
０００Ａ １２０００Ａ とし、例えば電子ビーム蒸着
装置スパッタ蒸着装置などによって一回の排気サイクル
中に行えばよい。また、熱処理は例えばＮ２雰囲気中で
４２０°Ｃ１８分間行う。第２図は、熱処理前の状態を
示しているが、熱処理によってＺｎ ？ ＩｎＧａＡｓ
Ｐ層１１中へ拡散きれて、ＩｎＧａＡｓＰ層１１表面に
層温１表面ｎドープ層が形成される。In this vapor deposition, for example, the film thickness of each layer is 1ooi and 1ooi, respectively.
000A to 12000A, and may be performed during one exhaust cycle using, for example, an electron beam evaporator or sputter evaporator. Further, the heat treatment is performed, for example, at 420° C. for 18 minutes in a N2 atmosphere. Figure 2 shows the state before heat treatment, but as a result of heat treatment, Zn? InGaAs
After being diffused into the P layer 11, a layer temperature 1 surface n-doped layer is formed on the surface of the InGaAsP layer 11.
しかし、Ａｕ層１５とＩｎＧａＡｓＰ層１１の相互層数
１Ｏｒ層１４によって阻止されているので、第１図の従
来例で示しだような合金層３は形成されない。従って、
ｐｌｊｌｌｎＰ閉込め層１６、Ｉ ｎ Ｇ ａ Ａ ｓ
Ｆ’（１，−外層１７にムＵが拡散していくおそれはな
い。ここで、本発明との直接的な関係はないが、ｎ型工
ｎＰ層１８、ｐ型ＩｎＰ層１９け埋込み層であり、ｎ型
ＩｎＰ基板２ｏ上にけＡｕ −Ｓｎ電極２１が形成きれ
ている。However, since the Au layer 15 and the InGaAsP layer 11 are prevented from forming by the Or layer 14, the alloy layer 3 as shown in the conventional example of FIG. 1 is not formed. Therefore,
pljllnP confinement layer 16, In Ga As
F'(1, - There is no fear that the mu will diffuse into the outer layer 17. Although this is not directly related to the present invention, the n-type InP layer 18 and the p-type InP layer 19 are buried layers. The Au--Sn electrode 21 has been completely formed on the n-type InP substrate 2o.
このようにして形成したオーミック電極のコンタクト抵
抗率を伝送線モデル（ＴＬＭ）法によって評価した。評
価した試料の形状は第２図に示したものとは異なるが、
基板の表面層と電極の構成法は全く同一である。第３図
は、４２０°Ｃで熱処理した場合の熱処理時間とコンタ
クト抵抗率の関係を示す。同図より４２ ｏＯＣで８分
間の熱処理を施すことにより良好なオーミック電極が形
成されることがわかる。また同図には、同一の基板に対
してＣｒ（１０００ｆ）、Ａｕ （２ｏｏｏＸ）のみを
蒸着熱処理した場合のコンタクト抵抗率と、Ｚｎの気相
拡散後Ｏｒ、Ａｕを蒸着熱処理した場合のコンタクト抵
抗率も示しである。これより、Ｏｒ、 Ａｕのみでオー
ミック電極を構成した場合ＶＣＶ′ｉ、電極蒸着前ｊｃ
Ｚｎの気相拡散を行うことか不可欠であることがわかる
。The contact resistivity of the ohmic electrode thus formed was evaluated using a transmission line model (TLM) method. Although the shape of the evaluated sample is different from that shown in Figure 2,
The construction methods for the surface layer of the substrate and the electrodes are exactly the same. FIG. 3 shows the relationship between heat treatment time and contact resistivity in the case of heat treatment at 420°C. It can be seen from the figure that a good ohmic electrode can be formed by heat treatment at 42 oC for 8 minutes. The same figure also shows the contact resistivity when the same substrate is heat-treated for vapor deposition of only Cr (1000f) and Au (2oooX), and the contact resistance when heat-treated for vapor deposition of Or and Au after vapor phase diffusion of Zn. The rate is also indicative. From this, when an ohmic electrode is composed of only Or and Au, VCV′i, jc before electrode deposition
It can be seen that it is essential to carry out vapor phase diffusion of Zn.
また、第２図に示した半導体レーザ（（対して寿命試験
を行った結果、第１図に示した合金化電極を用いたもの
に比べて大幅に特性が改善された。Furthermore, as a result of a life test performed on the semiconductor laser shown in FIG. 2, the characteristics were significantly improved compared to that using the alloyed electrode shown in FIG.
これ汀、先に述へたムＵの侵入による劣化が防止された
ためである。This is because the deterioration caused by the intrusion of the mucus mentioned above was prevented.
以上本発明を半導体レーザに適用した場合について説明
を行ったが、本発明は他のデバイス、例えば受光素子や
トランジスタに対しても適用可能である。また、化合物
半導体基板としてもｐ型ＩｎＣａＡｓＰのみに限定され
るものではなく、他の化合物半導体基板、例えばＩｎＰ
、 ＧａＡｓ 、 Ａ４ＣｒａＡｓ、ＧｌＬＰ等に対
しても適用可能である。この場合、ｎ型基板に対しては
Ｓ、 Ｓｅ、 Ｔｅ、 Ｇｅ、 Ｓｎ等が、ｐ型基板に
対してけＢｅ、 Ｍｇ、 Ｚｎ、 Ｃｄ等が不純物とな
る金属として用いられる。さらに、バリア金属としては
Ｃｒ以外にＴｉ、 Ｍｏ、Ｗ等を用いてもよく、電極母
材としてはＡｕ以外にＡｇ、 Ｐｔ、Ｐｄ、Ａノおよび
これらの金属よりなる多層膜を用いてもよい。Although the present invention has been described above in the case where it is applied to a semiconductor laser, the present invention can also be applied to other devices, such as light receiving elements and transistors. Furthermore, the compound semiconductor substrate is not limited to p-type InCaAsP, and may be other compound semiconductor substrates, such as InP.
, GaAs, A4CraAs, GlLP, etc. In this case, S, Se, Te, Ge, Sn, etc. are used as impurity metals for the n-type substrate, and Be, Mg, Zn, Cd, etc. are used as impurity metals for the p-type substrate. Further, as the barrier metal, Ti, Mo, W, etc. may be used in addition to Cr, and as the electrode base material, in addition to Au, Ag, Pt, Pd, Al, and a multilayer film made of these metals may be used. .
発明の効果
本発明によれは、電極蒸着前に気相拡散工程を必要とせ
す、かつコンタクト抵抗の低い非合金化オーミック電極
を構成することができる。また、このオーミック電極で
け合金層が形成されないの＋ ７・１１ｉ！Ｈ
”；＜ｂ＠＠ｓｓ“＠ｒ！ＰＫＫＪｔＨ，ｚｖき特性を
劣化させるという問題を生じることもない。Effects of the Invention According to the present invention, it is possible to construct a non-alloyed ohmic electrode that requires a vapor phase diffusion process before electrode deposition and has low contact resistance. Also, the alloy layer is not formed on this ohmic electrode +7・11i! H
”;<b@@ss“@r! There is no problem of deterioration of PKKJtH,zv characteristics.
第１図は従来のオーミック電極の断面図、第２図は本発
明の一実施例のオルミンク電極の断面図、第３図は熱処
理時間とコンタクト抵抗率の関係を示す特性図である。
１１ ・・化合物半導体基板、１３・・・第１の金属層
（Ｚｎ）、１４−−−第２の金属層（Ｃｒ ）、１６・
・・・第３の金属層（Ａｕ ）。
代理人の氏名 弁理士 中 尾 敏 男 ほか１名第１
図
第２図
第３図
塾ム理ｌＩ８眉（ｌか）FIG. 1 is a sectional view of a conventional ohmic electrode, FIG. 2 is a sectional view of an Olminc electrode according to an embodiment of the present invention, and FIG. 3 is a characteristic diagram showing the relationship between heat treatment time and contact resistivity. 11...Compound semiconductor substrate, 13...First metal layer (Zn), 14---Second metal layer (Cr), 16...
...Third metal layer (Au). Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Juku Murri I8 Eyebrow (l?)
Claims (1)
てｐ型もしくはｎ型の不純物となる金属よりなる第１の
金属層と、前記化合物半導体と電極母材の相互拡散を阻
止するバリア金属よりなる第２の金属層と、前記電極母
材よりなる第３の金属層を順次積層し、熱処理を施した
ことを特徴とするオーミック電極。A first metal layer made of a metal that acts as a p-type or n-type impurity for the compound semiconductor on a substrate made of a compound semiconductor, and a first metal layer made of a barrier metal that prevents mutual diffusion between the compound semiconductor and the electrode base material. An ohmic electrode characterized in that a second metal layer and a third metal layer made of the electrode base material are sequentially laminated and subjected to heat treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17194384A JPS6150363A (en) | 1984-08-18 | 1984-08-18 | Ohmic electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17194384A JPS6150363A (en) | 1984-08-18 | 1984-08-18 | Ohmic electrode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6150363A true JPS6150363A (en) | 1986-03-12 |
Family
ID=15932681
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17194384A Pending JPS6150363A (en) | 1984-08-18 | 1984-08-18 | Ohmic electrode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6150363A (en) |
-
1984
- 1984-08-18 JP JP17194384A patent/JPS6150363A/en active Pending
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