JPH03108779A - Formation of electrode of gallium nitride compound semiconductor - Google Patents
Formation of electrode of gallium nitride compound semiconductorInfo
- Publication number
- JPH03108779A JPH03108779A JP1247373A JP24737389A JPH03108779A JP H03108779 A JPH03108779 A JP H03108779A JP 1247373 A JP1247373 A JP 1247373A JP 24737389 A JP24737389 A JP 24737389A JP H03108779 A JPH03108779 A JP H03108779A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- gas
- etched
- compound semiconductor
- etching
- 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
- 229910002601 GaN Inorganic materials 0.000 title claims abstract description 36
- 239000004065 semiconductor Substances 0.000 title claims abstract description 20
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 12
- -1 gallium nitride compound Chemical class 0.000 title abstract description 5
- 239000007789 gas Substances 0.000 claims abstract description 50
- 150000001875 compounds Chemical class 0.000 claims abstract description 17
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 15
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 15
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000011737 fluorine Substances 0.000 claims abstract description 6
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 5
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052733 gallium Inorganic materials 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 13
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 claims description 11
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 4
- 239000000460 chlorine Substances 0.000 claims description 4
- 229910052801 chlorine Inorganic materials 0.000 claims description 4
- 239000011261 inert gas Substances 0.000 abstract description 7
- 239000000758 substrate Substances 0.000 abstract description 6
- PXBRQCKWGAHEHS-UHFFFAOYSA-N dichlorodifluoromethane Chemical compound FC(F)(Cl)Cl PXBRQCKWGAHEHS-UHFFFAOYSA-N 0.000 abstract description 5
- 235000019404 dichlorodifluoromethane Nutrition 0.000 abstract description 5
- 238000001312 dry etching Methods 0.000 abstract description 3
- 229910052594 sapphire Inorganic materials 0.000 abstract description 3
- 239000010980 sapphire Substances 0.000 abstract description 3
- 238000000151 deposition Methods 0.000 abstract 1
- 150000004767 nitrides Chemical class 0.000 abstract 1
- 238000005530 etching Methods 0.000 description 30
- 238000006243 chemical reaction Methods 0.000 description 12
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 10
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 10
- 229920002120 photoresistant polymer Polymers 0.000 description 7
- 238000005245 sintering Methods 0.000 description 7
- 229910052786 argon Inorganic materials 0.000 description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000001020 plasma etching Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- TXEYQDLBPFQVAA-UHFFFAOYSA-N tetrafluoromethane Chemical compound FC(F)(F)F TXEYQDLBPFQVAA-UHFFFAOYSA-N 0.000 description 3
- 238000007740 vapor deposition Methods 0.000 description 3
- 239000004338 Dichlorodifluoromethane Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 2
- 229950005499 carbon tetrachloride Drugs 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 150000004820 halides Chemical class 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- 238000000927 vapour-phase epitaxy Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 210000000078 claw Anatomy 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229910052743 krypton Inorganic materials 0.000 description 1
- DNNSSWSSYDEUBZ-UHFFFAOYSA-N krypton atom Chemical compound [Kr] DNNSSWSSYDEUBZ-UHFFFAOYSA-N 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 150000002902 organometallic compounds Chemical class 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- XCZXGTMEAKBVPV-UHFFFAOYSA-N trimethylgallium Chemical compound C[Ga](C)C XCZXGTMEAKBVPV-UHFFFAOYSA-N 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Abstract
Description
本発明は、オーミック性を改良した窒化ガリウム系化合
物半導体の電極形成方法および窒化ガリウム系発光素子
の製造方法に関する。The present invention relates to a method for forming an electrode of a gallium nitride compound semiconductor with improved ohmic properties and a method for manufacturing a gallium nitride light emitting device.
窒化ガリウム系化合物半導体は青色発光ダイオドとして
注目されている利料である。従来から検利されてきたハ
ライドＣＶＤ法では、ザファイア表面にＳｉＯ２やキズ
を形成し、その上に成長するポ１ＪＧａＮが低抵抗にな
ることを利用して選択的にコンタクト層（ｎ−ＧａＮか
ら電極をとる部分）を形成した。ところが、この成長方
法は成長の均一性に欠け、また、膜そのものの特性が不
充分なこともあり実用化されなかった。
現在、ハライドＣＶＤ法に代わって横側されているのが
ＭＯＶＰＥ （有機金属を使用した気相成長）法であり
、ＧａＮとザファイアの間に格子不整合の緩和のために
ＡＲＮ層を挿入した構造をとり、特性の優れたＧａＮ層
の成長に成功している。Gallium nitride-based compound semiconductors are attracting attention as blue light emitting diodes. In the conventional halide CVD method, SiO2 or scratches are formed on the surface of zaphire, and the contact layer (from n-GaN to electrode ) was formed. However, this growth method lacked uniformity of growth, and the film itself had insufficient characteristics, so it was not put to practical use. Currently, the MOVPE (metal-organic vapor phase epitaxy) method is being used in place of the halide CVD method, and it has a structure in which an ARN layer is inserted between GaN and zaphire to alleviate lattice mismatch. We have succeeded in growing a GaN layer with excellent characteristics.
しかしながら、ＭＯＶＰＥ法では、サファイア上の二１
−ズや５ｉｎ２． ＡＡ ２Ｄ３．５ｉＮＨ１１こは
ポリＧａＮは成長しない。したがって、１−ＧａＮ 層
からコンタクトをとるためには、１−ＧａＮ層のエツチ
ングとそのエツチング面上にオーミック性の良い電極を
形成する必要がある。
そこで、本発明者らは研究を重ねた結果、窒化ガリウム
系化合物半導体は炭素、塩素、フッ素を含む化合物、た
とえば、ジクロロジフルオロメタン（ＣＣｊｌ！２Ｆ２
）、テトラクロロメタン（ＣＣβ４）、テトラフルオロ
メタン（ＣＦ４）ガスのプラズマガスにてエツチングの
後、継続して、不活性ガス、たとえば、アルゴン（Ａｒ
）ガスのプラズマガスでエンチングした後、アルミニウ
ム電極を蒸着で形成すると、そのオーミック性が良いこ
とを発見し、本発明の完成に到った。
したがって、本発明の目的は、窒化ガリウム系化合物半
導体においてオーミック性の良い電極を形成することを
目的とする。However, in the MOVPE method, the
-zuya 5in2. AA 2D3.5iNH11 PolyGaN does not grow in this case. Therefore, in order to make contact from the 1-GaN layer, it is necessary to etch the 1-GaN layer and form an electrode with good ohmic properties on the etched surface. As a result of repeated research, the present inventors found that gallium nitride-based compound semiconductors are compounds containing carbon, chlorine, and fluorine, such as dichlorodifluoromethane (CCjl!2F2
), tetrachloromethane (CCβ4), and tetrafluoromethane (CF4) gas, and then etching with an inert gas, such as argon (Ar), is continued.
) It was discovered that the ohmic properties of aluminum electrodes are good when the aluminum electrodes are formed by vapor deposition after etching with plasma gas, leading to the completion of the present invention. Therefore, an object of the present invention is to form an electrode with good ohmic properties in a gallium nitride compound semiconductor.
上記課題を解決するための発明の構成は、少なくともガ
リウム及び窒素を含む化合物半導体において、アルミニ
ウム電極を形成する方法であって、前記化合物半導体の
電極形成部を炭素と、塩素又は／及びフッ素を含む化合
物ガスのプラズマガスでドライエツチングし、
その後に、そのエツチングされた電極形成部を不活性ガ
スのプラズマガスでドライエツチングし、その後に、前
記電極形成部にアルミニウムを蒸着するようにしたこと
である。
上記の少なくともガリウム及び窒素を含む化合物半導体
とは、ＧａＮ、 ＧａＡβＮであり、炭素と、塩素又は
／及びフッ素を含む化合物ガスとはジクロロジフルオロ
メタン（ＣＣｊ２２Ｉ’２）、テトラクロロメタン（Ｃ
Ｃβ４）、テトラフルオロメタン（Ｃ１ｉ４）ガスであ
り、不活性ガスとは、アルゴン（Ａｒ）、ヘリウム（ｌ
ｉｅ）、チッ素（Ｎ２）、クリプトン（Ｃ「）、キセノ
ン（Ｘｅ）ガスである。The structure of the invention for solving the above problem is a method of forming an aluminum electrode in a compound semiconductor containing at least gallium and nitrogen, the electrode forming portion of the compound semiconductor containing carbon, chlorine or/and fluorine. Dry etching is performed using a compound gas plasma gas, and then the etched electrode formation portion is dry etched using an inert gas plasma gas, and then aluminum is vapor-deposited on the electrode formation portion. . The compound semiconductors containing at least gallium and nitrogen are GaN and GaAβN, and the compound gases containing carbon and chlorine and/or fluorine are dichlorodifluoromethane (CCj22I'2), tetrachloromethane (C
Cβ4), tetrafluoromethane (C1i4) gas, and inert gases include argon (Ar), helium (L
ie), nitrogen (N2), krypton (C''), and xenon (Xe) gases.
発明者等の考察では、上記のＣＣ＃２Ｆ２． ＣＣｆｆ
４． ＣＩ’４のプラズマガスで窒化ガリウム化合物半
導体をドライエツチングするとき、そのエツチング部に
エツチングガス及び反応生成物の吸着等によりバリアが
形成されるために、アルミニウム電極のオミック性が良
くないと思われる。
そこで、本発明者らは実験を重ねた結果、プラズマエツ
チングの後に引き続いて、アルゴン等の不活性ガスでプ
ラズマエツチングを行い、その後に電極を形成すると、
良いオーミック性が得られることが判明した。According to the inventors' considerations, the above CC#2F2. CCff
4. When dry etching a gallium nitride compound semiconductor with CI'4 plasma gas, a barrier is formed in the etched area due to adsorption of the etching gas and reaction products, so the omic properties of the aluminum electrode are thought to be poor. . Therefore, as a result of repeated experiments, the inventors of the present invention found that if plasma etching is followed by plasma etching with an inert gas such as argon, and then electrodes are formed,
It was found that good ohmic properties could be obtained.
以下、本発明を具体的な実施例に基づいて説明する。
本実施例方法で使用された半導体は、有機金属化合物気
相成長法（以下ｒＭＯＶＰＩＥ Ｊと記す）による気相
成長により第２図に示す構造に作成された。
用いられたガスは、Ｎ１１３とキャリアガスＩＬとトリ
メチルガリウム（Ｇａ （ＣＩ１３） ３） （以下ｒ
ＴＭＧＪと記す）す１−リメチルアルミニウム（Δ］
（ＣＩ＋３） ３） （以下ｒＴＭＡｊと記す）である
。
まず、有機洗浄及び熱処理により洗浄した０面を主面と
する単結晶のザファイア基板１をＭＯＶＰＩＥ装置の反
応室に載置されたザセプタに装着する。
次に、反応室内の圧力を５Ｔｏｒｒに減圧し、１１２を
流速０．３１！／分で反応室に流しながら温度１１００
℃でザファイア基板１を気相エツチングした。
次に、温度を８００℃まで低下させて、１１２を流速３
β／分、Ｎ１１３を流速２１２／分、ＴＭＡを７Ｘ］、
Ｏ−’モル／分で供給して１分間熱処理した。この熱処
理によりＡ４２Ｎのバッファ層２が約５００人の厚さに
形成された。
次に、１分経過した時にＴＭＡの供給を停止して、ザフ
ァイア基板１の温度を１１５０℃に保持し、１１□を２
．５１１／分、Ｎ１１３を１．５ｆｆ／分、ＴＭＧを１
．．７Ｘ１０５モル／分で６０分間供給し、膜厚約３柳
のｎ型のＧａＮ層３を形成した。
次に、このようにして形成されたＧａＮ層３の上面にザ
ファイアから成るマスク４を第３図のように載置して試
料３．０を作成し、第１図に示す平行平板電極型のプラ
ズマエツチング装置により、露出したＧａＮ層３をエツ
チングした。
次に、そのエツチング装置について第１図を参照して説
明する。
第１図に示す平行電極型電極装置において、反心室２０
を形成するステンレス製の真空容器１゜の側壁には、エ
ツチング用のガスを導入する導入管１２．３４が連設さ
れており、その導入管１２．３４は、それぞれ、ガス流
速を可変できるマスフローコントローラ１４．３６を介
してＣＣｌ２１？２ガス、Ａｒガスを貯蔵したボンベ１
６．３８に接続されている。そして、ＣＣβ２Ｐ２ガス
、又はＡｒガスがそのボンベ１６．３８からマスフロー
コントローラ１４．３６を介して反応室２０に導入され
る。
又、反応室２０は拡散ポンプ１９により排気されており
、反応室２０の真空度は反応室２０と拡散ポンプ１９と
の間に介在するコンダクタンスバルブ１８により調整さ
れる。
一方、反応室２０内には」１下方向に対向して、電極２
２と電極２４とが配設されている。そして、電極２２は
接地され、電極２４には高周波電力が供給される。その
高周波電力は周波数１３．５６ＭＩ（ｚの高周波電源２
８から整合器２６を介して供給される。又、電極２４の
上には、第２図に示す構成の試料３０．３２が載置され
る。
係る構成の装置において、プラズマエツチングは次のよ
うにして行われる。
まず、試料３０等は、アセトン、トリクロロエチレン、
アセトンの順で、それぞれ、１０分間洗浄し、窒素を吹
き付けて乾燥させた後、王水（塩酸：硝酸−３：１）で
５分、純水で１０分洗浄して、窒素を吹き付けて乾燥さ
せた。その後、更に、２００℃ホットプレート上に５分
載置して脱水ベータした後、電極２４上にサファイア４
をマスクにして載置させた。
次に、拡散ポンプ１９により反応室２０内を十分に排気
して、反応室２０の真空度を５Ｘ］、Ｏ−’Ｔ。
ｒｒ以下にする。その後、ｃｃｘ２ｒ２ガスがマスフロ
ーコントローラ１４により流速１０ｃｃ／分に制御され
て反応室２０に導入され、コンダクタンスバルブ１８に
より反応室２０の真空度は正確に０．０４Ｔ。
ｒｒに調整された。そして、電極２４と電極２２間に０
．４４Ｗ／ｃｎｔの高周波電力が供給されて電極間でク
ロー放電が開始され、導入されたＣＣβ２Ｆ２ガスはプ
ラズマ状態となり、試料３０．３２のエツチングが開始
された。
８分間、エツチングを行った結果、試料３０は第４図に
示す構造にエツチングされた。即ち、マスク４で覆われ
たＧａＮ層３の部分はエツチングされず、露出したＧａ
Ｎ層４のみが図示する形状にエツチングされた。
次に、ＣＩＪ！２Ｆ２ガスの供給を停止して、アルゴン
（Ａｒ）ガスを１０分供給して、更に、エツチングした
。
最終的なエツチング深さは、最終的に８５００八であっ
た。
このようにして、エツチングした試料３０をエツチング
装置から取り出し、その試料３０をアセトン、トリクロ
ルエチレン、アセトンの順で、それぞれ、１０分間洗浄
し、窒素を吹き付けて乾燥させた。
その後、その試料に穴径２００−φ、 ５００帆ピツチ
の穴のあいたステンレス板をマスクとしてアルミニウム
を基板温度２２５℃、蒸着時の真空度３×］０６Ｔｏｒ
ｒで厚さ５０００八に蒸着して、第５図に示すように電
極６を形成した。
このようにして形成された電極６の電圧−電流特性（Ｖ
−Ｉ特性）を測定した。その結果を第６図（ｂ）に示す
。良好なオーミック特性が得られているのが分かる。
次に、上記の電極６の形成された試料３０を窒素雰囲気
中で５５０℃で１０分間、シンターしたが、オーミック
性に変化はなく、抵抗値が若干減少したに過ぎない。
又、アルゴン（Ａｒ）ガスのエツチング時間を１０分か
ら２０分に延長して、同様にアルミニウムの電極を形成
して、そのＶ−Ｉ特性を測定した。その結果を第６図（
Ｃ）に示す。若干、オーミック性が悪くなることが分か
る。しかし、その試料をシンターすると、第６図（ロ）
に示すように、オーミック性が改善されることが理解さ
れる。
したがって、シンターせずに、良好なオーミック性を得
るためには、Ａｒガスのエツチング時間は１０分程度が
望ましいことが分かる。
尚、比較例として、ＣＣｌ２２１’２ガスでのみエツチ
ングして、Ａ「ガスでエツチングしなかった場合の特０
性は、第６図（ａ）に示すようになり、オーミック性は
得られなかった。又、この試料をシンターした後の特性
は、第６図（ｆ）に示すようになり、特性の改善は見ら
れなかった。
更に、ＣＣｌ２Ｆ２とＡｒの混合ガスでエツチングして
電極を形成した場合の特性は、第６図（ｄ）に示すよう
に、オーミック性は得られなかった。又、その試料をシ
ンターしても、第６図（ｉ）に示すように、オーミック
性の改善は見られなかった。
更に、最初からＡｒガスでエツチングして電極を形成し
た場合の特性は、第６図（ｅ）に示すように、やはりオ
ーミック性は得られなかった。又、その試料をシンター
した後の特性も、第６図（ｊ）に示しように、オーミッ
ク性の改善が得られなかった。
又、ｃｃｈ２ｐ２ガスでエツチングしていない窒化ガリ
ウム半導体に直接、アルミニウム電極を蒸着した場合の
特性を測定した。その特性結果を第７図（ａ）−（ｅ）
に示す。又、その試料をシンターした後に測定した特性
を第７図（ｆ）−（ｊ）に示す。シンター前では、オー
ミック性は得られていないがシンタによりオーミック性
が得られるのが分かる。しかし、そのオーミック性にバ
ラツキがあることも分かる。
以上のことから、ＣＣβ２Ｆ２ガスにより窒化ガリウム
半導体をエツチングしてそのエツチング部分にアルミニ
ウム電極を形成すると、その電極のＶ■特性は、シンタ
ーによっても改善できない非オーミツク性を示すことが
理解される。
しかし、ＣＣβ２Ｐ２ガスでエツチングした後、Ａｒガ
スで継続してエツチングして電極を形成すると、シンタ
ーすることなく、当初から良好なオーミック性が得られ
ることが分かった。
又、本発明者等の考察では、上記のＡｒガスによる継続
エツチングが、先行するＣＣβ２Ｐ２ガス又はＣＣβ４
ガス又はｃｐ４ガスのエツチングによって生じるエツチ
ングガス及び反応生成物の吸着等によって形成されたバ
リアを除去するものと思われる。
したがって、その後のバリア除去のためのエツチングに
使用されるガスとしては、Ａ「ガスと同様な効果がある
と予測される他の不活性ガスの使用も可能である。
次に、本発明の電極形成方法を用いた窒化ガリウム系発
光素子の製造方法について説明する。
第８図に示すように、前述した条件により、ＭＯＣＶＤ
法によりザファイア基板１上に、ＡβＮから成るバッフ
ァ層２を５００への厚さに形成し、そのバッファ層２の
上にｎ−ＧａＮ層３を３ノ鹿の厚さに形成した。そして
、そのｎ−ＧａＮ層３」二に１−ＧａＮ層４０を成長温
度９００℃で膜厚２５００人の厚さに形成した。
次に、第９図に示すように、１−ＧａＮ層４０の上に、
スパッタリングにより８１０２層４１を２０００への厚
さに形成した。次に、その５層０２層４１上にフォトレ
ジスト４２を塗布して、フォトリソグラフにより、ｎ−
ＧａＮ層３に対する電極形成部位のフォトレジスト
次に、第１０図に示すように、フォトレジスト４２によ
って覆われていないＳ１０２層４１をフッ酸系エツチン
グ液で除去した。
次に、第１１図に示すように、フォトレジスト４２及び
Ｓｉ０２層４１によって覆われていない部位のｉ−Ｇａ
Ｎ層４０及びその下のｎ−ＧａＮ層３の一部を、前述し
た条件で、ＣＣｌ２Ｆ２でエツチングした後、八ｒでド
ライエツチングした。
次に、第１２図に示すように、ｉ−ＧａＮ層４０」−に
残っている３１０２層４］をフッ酸で除去した。
次に、第１３図に示すように、試料の」二全面に前述し
た条件により、Ａβ層４３を蒸将により形成した。そし
て、そのＡ１層４３の」−にフォトレジスト４４を塗布
して、フォトリックラフにより、ｎＧａＮ層３及びｉ
−Ｇ ａ ｔ４層４０に対する電極部が残るように、所
定形状にパターン形成した。次に、第１４図に示すよう
にそのフォトレジスト４４をマスクとして下層のＡ１層
４３の露出部を硝酸系エツチング液でエツチングし、フ
ォトレジストアセトンで除去し、ｎ−ＧａＮ層３の電極
４５、ｉ−ＧａＮ層４０の電極４６を形成した。
このようにして、ＭＩＳ （Ｍｅｔａｌ−１ｎｓｕｌａ
ｔｅｒ−Ｓｅｍｉｃ。
ｎｄｕｃｔｏｒ）構造の窒化ガリウム系発光素を製造す
ることができる。The present invention will be described below based on specific examples. The semiconductor used in the method of this example was formed into the structure shown in FIG. 2 by vapor phase growth using organometallic compound vapor phase epitaxy (hereinafter referred to as rMOVPIE J). The gases used were N113, carrier gas IL, and trimethyl gallium (Ga (CI13) 3) (hereinafter r
TMGJ) 1-trimethylaluminum (Δ]
(CI+3) 3) (hereinafter referred to as rTMAj). First, a single-crystal zaphire substrate 1, which has been cleaned by organic cleaning and heat treatment and whose main surface is the 0 side, is mounted on a zaceptor placed in a reaction chamber of a MOVPIE apparatus. Next, the pressure inside the reaction chamber was reduced to 5 Torr, and the flow rate of 112 was 0.31! The temperature was increased to 1100°C while flowing into the reaction chamber at a rate of
The Zaphire substrate 1 was subjected to vapor phase etching at .degree. Next, the temperature was lowered to 800°C and the flow rate of 112 was 3.
β/min, N113 flow rate 212/min, TMA 7X],
Heat treatment was performed for 1 minute by supplying O-'mol/min. Through this heat treatment, the buffer layer 2 of A42N was formed to a thickness of approximately 500 nm. Next, when 1 minute has passed, the supply of TMA is stopped, the temperature of the Zaphire substrate 1 is maintained at 1150°C, and 11□ is
．． 511/min, N113 1.5ff/min, TMG 1
．． ．． It was supplied for 60 minutes at a rate of 7×10 5 mol/min to form an n-type GaN layer 3 with a thickness of about 3 yen. Next, a mask 4 made of zaphire was placed on the upper surface of the GaN layer 3 thus formed as shown in FIG. The exposed GaN layer 3 was etched using a plasma etching device. Next, the etching apparatus will be explained with reference to FIG. In the parallel electrode type electrode device shown in FIG.
Introductory pipes 12.34 for introducing etching gas are connected to the side wall of the stainless steel vacuum vessel 1° forming the etching process. Cylinder 1 storing CCl21?2 gas and Ar gas via controller 14.36
6.38 is connected. Then, CCβ2P2 gas or Ar gas is introduced into the reaction chamber 20 from the cylinder 16.38 via the mass flow controller 14.36. Further, the reaction chamber 20 is evacuated by a diffusion pump 19, and the degree of vacuum in the reaction chamber 20 is adjusted by a conductance valve 18 interposed between the reaction chamber 20 and the diffusion pump 19. On the other hand, in the reaction chamber 20, an electrode 2 is placed facing downwardly.
2 and an electrode 24 are provided. The electrode 22 is grounded, and the electrode 24 is supplied with high frequency power. The high frequency power has a frequency of 13.56 MI (high frequency power supply 2 of z)
8 through a matching box 26. Further, on the electrode 24, samples 30 and 32 having the configuration shown in FIG. 2 are placed. In an apparatus having such a configuration, plasma etching is performed as follows. First, sample 30 etc. are acetone, trichlorethylene,
Wash with acetone for 10 minutes, spray with nitrogen and dry, wash with aqua regia (hydrochloric acid: nitric acid - 3:1) for 5 minutes, then with pure water for 10 minutes, spray with nitrogen and dry. I let it happen. Thereafter, after further dehydration by placing on a 200°C hot plate for 5 minutes, sapphire
was placed as a mask. Next, the inside of the reaction chamber 20 was sufficiently evacuated by the diffusion pump 19, and the degree of vacuum in the reaction chamber 20 was set to 5X], O-'T. Make it below rr. Thereafter, ccx2r2 gas was introduced into the reaction chamber 20 at a flow rate of 10 cc/min by the mass flow controller 14, and the degree of vacuum in the reaction chamber 20 was set to exactly 0.04T by the conductance valve 18. Adjusted to rr. Then, 0 is applied between the electrode 24 and the electrode 22.
．． A high frequency power of 44 W/cnt was supplied to start claw discharge between the electrodes, the introduced CCβ2F2 gas became a plasma state, and etching of sample 30.32 was started. As a result of etching for 8 minutes, sample 30 was etched into the structure shown in FIG. That is, the portion of the GaN layer 3 covered by the mask 4 is not etched, and the exposed GaN layer 3 is not etched.
Only the N layer 4 was etched into the shape shown. Next, CIJ! The supply of 2F2 gas was stopped, and argon (Ar) gas was supplied for 10 minutes for further etching. The final etching depth was 8,500 mm. The etched sample 30 was taken out of the etching apparatus, washed with acetone, trichlorethylene, and acetone for 10 minutes each, and dried by blowing nitrogen. Thereafter, using a stainless steel plate with holes of 200-φ and 500 pitch as a mask, aluminum was deposited on the sample at a substrate temperature of 225°C and a vacuum degree of 3×]06 Tor during vapor deposition.
The electrode 6 was formed as shown in FIG. 5 by vapor deposition to a thickness of 5,000 mm. The voltage-current characteristics (V
-I characteristics) were measured. The results are shown in FIG. 6(b). It can be seen that good ohmic characteristics are obtained. Next, the sample 30 on which the electrode 6 was formed was sintered at 550° C. for 10 minutes in a nitrogen atmosphere, but there was no change in ohmic properties, and the resistance value was only slightly reduced. Further, the argon (Ar) gas etching time was extended from 10 minutes to 20 minutes, an aluminum electrode was formed in the same manner, and its VI characteristics were measured. The results are shown in Figure 6 (
Shown in C). It can be seen that the ohmic properties deteriorate slightly. However, when the sample is sintered, Fig. 6 (b)
It is understood that the ohmic properties are improved as shown in FIG. Therefore, it can be seen that in order to obtain good ohmic properties without sintering, it is desirable that the Ar gas etching time be about 10 minutes. As a comparative example, etching was performed only with CCl221'2 gas, and the characteristics when etching was not performed with A" gas were as shown in Figure 6 (a), and ohmic properties were not obtained. In addition, the characteristics after sintering this sample became as shown in Figure 6(f), and no improvement in characteristics was observed.Furthermore, electrodes were formed by etching with a mixed gas of CCl2F2 and Ar. In this case, as shown in Figure 6(d), no ohmic property was obtained.Also, even if the sample was sintered, the ohmic property was not improved as shown in Figure 6(i). Furthermore, when the electrode was formed by etching with Ar gas from the beginning, ohmic properties were not obtained as shown in Figure 6(e). As shown in Figure 6 (j), no improvement in ohmic properties was obtained after etching.Also, the characteristics when an aluminum electrode was deposited directly on a gallium nitride semiconductor that had not been etched with cch2p2 gas. The characteristic results are shown in Figure 7(a)-(e).
Shown below. Further, the characteristics measured after sintering the sample are shown in FIGS. 7(f)-(j). It can be seen that ohmic properties are not obtained before sintering, but ohmic properties are obtained by sintering. However, it can also be seen that there are variations in the ohmic nature. From the above, it is understood that when a gallium nitride semiconductor is etched with CCβ2F2 gas and an aluminum electrode is formed in the etched portion, the V.sub.2 characteristic of the electrode exhibits non-ohmic properties that cannot be improved even by sintering. However, it has been found that if electrodes are formed by etching with CCβ2P2 gas and then continuously etching with Ar gas, good ohmic properties can be obtained from the beginning without sintering. In addition, according to the inventors' considerations, the continuous etching using Ar gas described above is effective against the preceding CCβ2P2 gas or CCβ4
It is believed that the barrier formed by adsorption of etching gas and reaction products generated by etching gas or CP4 gas is removed. Therefore, as the gas used for the subsequent etching to remove the barrier, it is also possible to use other inert gases that are expected to have the same effect as gas A. A method for manufacturing a gallium nitride-based light emitting device using the formation method will be explained.As shown in FIG.
A buffer layer 2 made of AβN was formed to a thickness of 500 mm on a zaphire substrate 1 by a method, and an n-GaN layer 3 was formed on the buffer layer 2 to a thickness of 3 mm. Then, the n-GaN layer 3'' and the 1-GaN layer 40 were formed to a thickness of 2500 nm at a growth temperature of 900°C. Next, as shown in FIG. 9, on the 1-GaN layer 40,
An 8102 layer 41 was formed to a thickness of 2000 nm by sputtering. Next, a photoresist 42 is applied on the 5th layer 02 layer 41, and an n-
Photoresist at Electrode Formation Site for GaN Layer 3 Next, as shown in FIG. 10, the S102 layer 41 not covered by the photoresist 42 was removed using a hydrofluoric acid etching solution. Next, as shown in FIG.
The N layer 40 and a part of the n-GaN layer 3 thereunder were etched with CCl2F2 under the conditions described above, and then dry etched with 8R. Next, as shown in FIG. 12, the 3102 layer 4] remaining on the i-GaN layer 40'' was removed with hydrofluoric acid. Next, as shown in FIG. 13, an Aβ layer 43 was formed on the entire surface of the sample using a steamer under the conditions described above. Then, a photoresist 44 is applied to the "-" of the A1 layer 43, and the nGaN layer 3 and the i
- A pattern was formed in a predetermined shape so that an electrode portion for the Ga t4 layer 40 remained. Next, as shown in FIG. 14, using the photoresist 44 as a mask, the exposed portion of the lower A1 layer 43 is etched with a nitric acid-based etching solution and removed with photoresist acetone. An electrode 46 of the i-GaN layer 40 was formed. In this way, MIS (Metal-1nsula
ter-Semic. It is possible to manufacture a gallium nitride-based light-emitting device with a gallium nitride structure.
３
４
第１図は本発明の具体的な一実施例に係るエツチング方
法を実現するだめの装置を示した構成図。
第２図はエツチング試料の構成を示した断面図。
第３図はエツチング試料とマスクとの関係を示した断面
図。第４図はエツチング後の試料の断面図。
第５図はエツチング部に電極を形成した試料の断面図。
第６図は各種の条件でエツチングした窒化ガリウム半導
体に形成した電極のＶ−■特性の測定図。第７図はエツ
チングしない窒化ガリウム半導体に形成した電極のＶ−
Ｉ特性の測定図。第８図乃至第１４図は本発明の電極形
成方法を用いた窒化ガリウム系発光素子の製造工程を示
す断面図である。
コンダクタンスバルブ
高周波電源
１−ＧａＮ層 ４１
フォトレジスト層
４６ 電極
５ｉ０２層
３
２２．２４
へβ層3 4 FIG. 1 is a block diagram showing an apparatus for realizing an etching method according to a specific embodiment of the present invention. FIG. 2 is a sectional view showing the structure of an etched sample. FIG. 3 is a sectional view showing the relationship between the etching sample and the mask. FIG. 4 is a cross-sectional view of the sample after etching. FIG. 5 is a cross-sectional view of a sample with electrodes formed on the etched portion. FIG. 6 is a measurement diagram of the V-■ characteristics of electrodes formed on gallium nitride semiconductors etched under various conditions. Figure 7 shows the V-
A measurement diagram of I characteristics. FIGS. 8 to 14 are cross-sectional views showing the manufacturing process of a gallium nitride-based light emitting device using the electrode forming method of the present invention. Conductance valve high frequency power supply 1-GaN layer 41 Photoresist layer 46 Electrode 5i02 layer 3 22.24 to β layer
Claims (1)
て、アルミニウム電極を形成する方法であって、 前記化合物半導体の電極形成部を炭素と、塩素又は／及
びフッ素を含む化合物ガスのプラズマガスでドライエッ
チングし、 その後に、そのエッチングされた電極形成部を不活性ガ
スのプラズマガスでドライエッチングし、その後に、前
記電極形成部にアルミニウムを蒸着することを特徴とす
る窒化ガリウム系化合物半導体の電極形成方法。[Claims] A method for forming an aluminum electrode in a compound semiconductor containing at least gallium and nitrogen, the electrode forming portion of the compound semiconductor being treated with a plasma gas of a compound gas containing carbon and chlorine or/and fluorine. An electrode of a gallium nitride-based compound semiconductor, characterized in that the electrode is dry-etched, the etched electrode formation part is dry-etched with an inert plasma gas, and then aluminum is vapor-deposited on the electrode formation part. Formation method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24737389A JP2623463B2 (en) | 1989-09-22 | 1989-09-22 | Gallium nitride based compound semiconductor electrode forming method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24737389A JP2623463B2 (en) | 1989-09-22 | 1989-09-22 | Gallium nitride based compound semiconductor electrode forming method |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3265896A Division JP2706660B2 (en) | 1996-01-26 | 1996-01-26 | Gallium nitride based compound semiconductor electrode forming method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03108779A true JPH03108779A (en) | 1991-05-08 |
| JP2623463B2 JP2623463B2 (en) | 1997-06-25 |
Family
ID=17162467
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24737389A Expired - Fee Related JP2623463B2 (en) | 1989-09-22 | 1989-09-22 | Gallium nitride based compound semiconductor electrode forming method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2623463B2 (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH053928U (en) * | 1991-06-28 | 1993-01-22 | 豊田合成株式会社 | Luminous pointer |
| JPH05183189A (en) † | 1991-11-08 | 1993-07-23 | Nichia Chem Ind Ltd | Manufacture of p-type gallium nitride based compound semiconductor |
| JPH05211347A (en) * | 1991-07-23 | 1993-08-20 | Toyoda Gosei Co Ltd | Gallium nitride compound semiconductor light-emitting element |
| EP0834929A2 (en) * | 1996-10-03 | 1998-04-08 | Toyoda Gosei Co., Ltd. | Ohmic contact to n-GaN related compound semiconductor and its manufacturing method |
| US5811319A (en) * | 1995-03-27 | 1998-09-22 | Toyoda Gosei Co., Ltd. | Methods of forming electrodes on gallium nitride group compound semiconductors |
| JP2002261326A (en) * | 2001-03-02 | 2002-09-13 | Nagoya Kogyo Univ | Method of manufacturing gallium nitride compound semiconductor element |
| JP2006173386A (en) * | 2004-12-16 | 2006-06-29 | Eudyna Devices Inc | Semiconductor device, semiconductor module provided therewith, and method for manufacturing semiconductor device |
| WO2013132783A1 (en) * | 2012-03-07 | 2013-09-12 | パナソニック株式会社 | Nitride semiconductor laminate structure, nitride semiconductor light emitting element provided with nitride semiconductor laminate structure, and method for producing nitride semiconductor laminate structure |
| US9287378B2 (en) | 2013-07-19 | 2016-03-15 | Panasonic Intellectual Property Management Co., Ltd. | Nitride semiconductor light-emitting element and method for fabricating the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6996150B1 (en) | 1994-09-14 | 2006-02-07 | Rohm Co., Ltd. | Semiconductor light emitting device and manufacturing method therefor |
-
1989
- 1989-09-22 JP JP24737389A patent/JP2623463B2/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH053928U (en) * | 1991-06-28 | 1993-01-22 | 豊田合成株式会社 | Luminous pointer |
| JPH05211347A (en) * | 1991-07-23 | 1993-08-20 | Toyoda Gosei Co Ltd | Gallium nitride compound semiconductor light-emitting element |
| JPH05183189A (en) † | 1991-11-08 | 1993-07-23 | Nichia Chem Ind Ltd | Manufacture of p-type gallium nitride based compound semiconductor |
| US5811319A (en) * | 1995-03-27 | 1998-09-22 | Toyoda Gosei Co., Ltd. | Methods of forming electrodes on gallium nitride group compound semiconductors |
| EP0834929A2 (en) * | 1996-10-03 | 1998-04-08 | Toyoda Gosei Co., Ltd. | Ohmic contact to n-GaN related compound semiconductor and its manufacturing method |
| EP0834929A3 (en) * | 1996-10-03 | 1998-04-22 | Toyoda Gosei Co., Ltd. | Ohmic contact to n-GaN related compound semiconductor and its manufacturing method |
| JP2002261326A (en) * | 2001-03-02 | 2002-09-13 | Nagoya Kogyo Univ | Method of manufacturing gallium nitride compound semiconductor element |
| JP2006173386A (en) * | 2004-12-16 | 2006-06-29 | Eudyna Devices Inc | Semiconductor device, semiconductor module provided therewith, and method for manufacturing semiconductor device |
| JP4597653B2 (en) * | 2004-12-16 | 2010-12-15 | 住友電工デバイス・イノベーション株式会社 | Semiconductor device, semiconductor module including the same, and method for manufacturing semiconductor device |
| WO2013132783A1 (en) * | 2012-03-07 | 2013-09-12 | パナソニック株式会社 | Nitride semiconductor laminate structure, nitride semiconductor light emitting element provided with nitride semiconductor laminate structure, and method for producing nitride semiconductor laminate structure |
| US9287378B2 (en) | 2013-07-19 | 2016-03-15 | Panasonic Intellectual Property Management Co., Ltd. | Nitride semiconductor light-emitting element and method for fabricating the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2623463B2 (en) | 1997-06-25 |
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