JP4150789B2 - Amorphous carbon nitride film and manufacturing method thereof - Google Patents

Amorphous carbon nitride film and manufacturing method thereof Download PDF

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JP4150789B2
JP4150789B2 JP2003005299A JP2003005299A JP4150789B2 JP 4150789 B2 JP4150789 B2 JP 4150789B2 JP 2003005299 A JP2003005299 A JP 2003005299A JP 2003005299 A JP2003005299 A JP 2003005299A JP 4150789 B2 JP4150789 B2 JP 4150789B2
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substrate
nitride film
amorphous carbon
carbon nitride
plasma
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草児 宮川
佳子 宮川
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National Institute of Advanced Industrial Science and Technology AIST
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Description

【０００１】
【発明の属する技術分野】
本発明は、非晶質の窒化炭素膜の形成方法、及び非晶質窒化炭素膜−基材複合体の製造方法に関するものであり、更に詳しくは、基材に、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を形成して成る高導電性非晶質窒化炭素膜−基材複合体を製造する方法、及び該方法により作製した複合体に関するものである。本発明は、燃料電池用セパレータ他、各種電極、スイッチ接点など複雑形状を有する導電性基材に、高導電性、高耐食性、及び高密着性の非晶質窒化炭素膜を形成する方法、及びその製品を提供するものとして有用である。
【０００２】
【従来の技術】
従来、例えば、燃料電池のセパレータ（バイポーラ板）の材料としては、電解質膜が強酸性であるため、また、良好な導電性が必要であるため、多くの場合、ガス不浸透性の炭素板が使われている。その表面には、ガス流路を形成するための溝加工が施される。従来、この材料としては、黒鉛の塊から切り出した板を使っていたが、コストの低減のために、手間のかかる機械加工を必要としない樹脂モールドカーボン、及び膨張化黒鉛基材のガス不浸透性炭素膜を、加圧成型で溝やマニホールドを形成する方法、また、炭素に樹脂やピッチを加え、成形し、焼成／炭化して、炭素・炭素複合材料とする方法、が検討されている。この他に、チタンやステンレスなどの金属や金属と炭素の複合材料も検討されている。
【０００３】
しかし、金属は、燃料電池の材料として使う場合、その表面が腐食されやすく、接触抵抗が増加する傾向があり、そのため、表面を貴金属でメッキするなどの対策が必要とされている。また、ステンレスなどの金属材料に非晶質炭素（ＤＬＣ）膜をコーティングする方法も提案されている。これらの材料を基材にコーティングする方法としては、例えば、スパッタリング法、電子ビーム蒸着法、カーボン塗装などがあるが、いずれも密着性、着き回り性、電気伝導性などが充分でなく、使用できない、という問題がある。また、非晶質炭素膜を高温にして炭化する方法は、基材を８００℃以上に加熱する必要があり、基材の熱変形などのために適用できない、という問題がある。一方、例えば、燃料電池セパレート板においては、溝などを有する複雑形状を有する金属薄板上に電気導電性、及び耐食性に優れた炭素材料をコーティングする技術が要求されている。
【０００４】
従来、非晶質窒化炭素膜を製造する方法及び装置として、例えばレーザーアブレーションを用いた方法（特許文献１参照) 、グラファイト電極と窒素ガスのピンチプラズマを利用した方法（特許文献２参照) 、プラズマ化学的気相成長法及びイオンビーム堆積法を用いた方法（特許文献３参照) 、炭素蒸気と窒素イオンビームを組み合わせた方法（特許文献４参照) 、高周波マグネトロンスパッタリングを用いた方法（特許文献５参照) 、などが提案されている。しかしながら、これらの先行技術は、例えば、電気導電性、耐食性及び密着性の点で更に改善すること、低温（基材温度３００℃以下) で高導電性のコーティング膜を形成する方法を開発することが強く要請されていた。しかしながら、これらの先行技術は、例えば、電気導電性、密着性等の面で未だ実用化の域に達しておらず、当該技術分野では、電気導電性、耐食性及び密着性の点で更に改善すること、低温（３００℃以下）で非晶質炭素膜の高導電性膜を形成する方法を開発すること、が強く要請されていた。
【０００５】
【特許文献１】
特開平１１−２２９１２４号公報
【特許文献２】
特開２００１−５９１５６号公報
【特許文献３】
特開２０００−２８５４３７号公報
【特許文献４】
特開平１１−２０９８６８号公報
【特許文献５】
特開平１１−２３８６８４号公報
【０００６】
【発明が解決しようとする課題】
このような状況の中で、本発明者らは、上記従来技術に鑑みて、上記従来技術の諸問題を抜本的に解決することを可能とする新しい技術を開発することを目標として鋭意研究を積み重ねた結果、基材表面のミキシング層の形成工程、炭化水素及び窒素のプラズマの生成と正イオンの基材への照射工程、及び高電圧正パルスの基材への印加とプラズマ中の電子の基材への照射工程を組み合わせてそれらの処理条件を調整することにより、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を形成し得ることを見出し、本発明を完成するに至った。
【０００７】
本発明は、基材に低温（３００℃以下）で、優れた電気導電性（接触抵抗１０ｍΩ／ｃｍ2 以下）を有する非晶質窒化炭素薄膜を形成する方法を提供することを目的とするものである。
また、本発明は、金属製基材との密着性に優れた非晶質窒化炭素薄膜の製造方法を提供することを目的とするものである。
また、本発明は、燃料電池用セパレータ等溝加工を施した（複雑形状の）金属薄板上へ、高密着性、高電気電導性、及び高耐食性の非晶質窒化炭素膜をコーティングする方法を提供することを目的とするものである。
更に、本発明は、複雑形状の基材に、電気伝導性、耐食性、及び密着性に優れた非晶質窒化炭素膜を低コストで、効率良く生産する方法を提供することを目的とするものである。
【０００８】
【課題を解決するための手段】
上記課題を解決するための本発明は、以下の技術的手段から構成される。
（１）導電性基材に、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を形成する方法であって、
（ａ）真空槽で基材をメタンガスプラズマ中に浸し、プラズマ中の正イオンを基材に照射し、表層にイオン注入によるミキシング層を形成する、
（ｂ）炭化水素と窒素の混合ガスを真空槽に導入し、プラズマを生成させ、これらのラジカルを基材表面に堆積させるとともに、基材に、負電圧を印加し、正イオンを加速して基材に照射する、
（ｃ）その際に、正高電圧パルス（好適には３〜１５ｋＶ）を基材に印加し、プラズマ中の電子を高エネルギーで基材に照射することによって、表層のみをパルス的に活性化、及び高温状態にする、
（ｄ）上記（ａ）〜（ｃ）により、１４０℃又はそれより高温で３００℃又はそれより低温の基材に炭化水素及び窒素のラジカル及びイオンを堆積させ、抵触抵抗が１０ｍΩ／ｃｍ ２ 又はそれより小さい値で、電気抵抗率が１ｋΩ・ｃｍより小さい値を有する高導電性の非晶質窒化炭素膜を形成する、
ことを特徴とする非晶質窒化炭素膜の形成方法。
（２）導電性基材に、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を形成して成る高導電性非晶質窒化炭素膜−基材複合体を製造する方法であって、
（ａ）真空槽で基材をメタンガスプラズマ中に浸し、プラズマ中の正イオンを基材に照射し、表層にイオン注入層を形成する、
（ｂ）炭化水素と窒素の混合ガスを真空槽に導入し、プラズマを生成させ、これらのラジカルを基材表面に堆積させるとともに、基材に、負電圧を印加し、正イオンを加速して基材に照射する、
（ｃ）その際に、高電圧正パルスを基材に印加し、プラズマ中の電子を高エネルギーで基材に照射することによって、表層のみをパルス的に活性化、及び高温状態にする、
（ｄ）上記（ａ）〜（ｃ）により、１４０℃より高温で３００℃より低温の基材に炭化水素及び窒素のラジカル及びイオンを堆積させ、抵触抵抗が１０ｍΩ／ｃｍ ２ 又はそれより小さい値で、電気抵抗率が１ｋΩ・ｃｍより小さい値を有する高導電性の非晶質窒化炭素膜を形成した高導電性非晶質窒化炭素膜−基材複合体を製造する、
ことを特徴とする高導電性非晶質窒化炭素膜−基材複合体の製造方法。
（３）基材が、複雑形状を任意に有する金属薄板である前記（１）又は（２）記載の方法。
（４）基材が、複雑形状を有する電極である前記（３）記載の方法。
（５）基材が、複雑形状を有するスイッチ接点である前記（３）記載の方法。
（６）前記（２）から（５）のいずれかに記載の方法により製造された、基材に、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を堆積してなる、抵触抵抗が１０ｍΩ／ｃｍ ２ 又はそれより小さい値で、電気抵抗率が１ｋΩ・ｃｍより小さい値を有する高導電性非晶質窒化炭素膜−基材複合体。
（７）前記（６）記載の複合体を構成要素として含む電極又はスイッチ接点用高導電性部材。
（８）燃料電池用セパレータである前記（７）記載の高導電性部材。
【０００９】
【発明の実施の形態】
本発明は、前述のように、主に、基材に、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を形成して成る高導電性非晶質窒化炭素膜−基材複合体を製造する方法であって、（ａ）真空槽で基材をメタンガスプラズマ中に浸し、プラズマ中の正イオンを基材に照射し、表層にイオン注入層を形成する、（ｂ）炭化水素と窒素の混合ガスを真空槽に導入し、プラズマを生成させ、これらのラジカルを基材に堆積させるとともに、基材に、負電圧を印加し、正イオンを加速して基材に照射する、（ｃ）その際に、正高電圧パルスを基材に印加し、プラズマ中の電子を基材に照射することにより、表層のみをパルス的に活性化、及び高温状態にする、（ｄ）上記（ａ）〜（ｃ）により、基材に炭化水素及び窒素のラジカル及びイオンを堆積させ、高導電性の非晶質窒化炭素膜を形成した高導電性の非晶質窒化炭素膜−基材複合体を製造する、ことを特徴とするものである。
【００１０】
本発明では、まず、メタンプラズマ中に置いた基材に、負高電圧パルスを印加することによって、基材の全方向からメタンイオン照射を行い、イオン注入によって、炭素原子の分散した導電性皮膜を形成する。次に、トルエンなど分子量の大きい炭化水素及び窒素ガスを同時的に真空槽に導入し、高周波放電、グロー放電などによって、これらのプラズマを生成し、基材に、負電圧を印加し、正イオンを基材に照射する。この際に、高電圧正パルスを基材に印加し、プラズマ中の電子を基材に照射することによって、表層のみをパルス的に活性化、及び高温状態にし、基材の温度を上昇させることなく、炭化水素及び窒素プラズマを堆積させる。本発明は、これらの工程を有機的に組み合わせることにより、例えば、複雑形状の基材に、高導電性、高耐食性、及び高密着性の非晶質窒化炭素膜を形成することができる。
【００１１】
本発明において、プラズマの生成は、好適には、例えば、グロー放電、高周波放電（ＲＦ）、電子サイクロトン共鳴（ＥＣＲ）放電、及びこれらの組み合わせによるパルスプラズマ生成により行うことができるが、これらに制限されるものではなく、あらゆる方法及び装置を用いることが可能である。また、本発明では、炭化水素化合物ＣｘＨｙのプラズマ放電によるイオンを用いた非晶質炭素の堆積（デポジション）による膜形成が行われるが、上記炭化水素化合物ＣｘＨｙとして、ｘ＝１〜１０、ｙ＝２〜２２の炭化水素が好適に用いられる。
【００１２】
本発明において、メタンガスプラズマからの炭素イオンによる表層へのイオン注入層の形成のための条件は、好適には、例えば、ガス条件として、ガス種はメタン、ガス流量は５〜１０ｓｃｃｍ、真空度（プロセス時）は２〜５×１０-4Ｔｏｒｒ程度、パルス印加条件として、正パルスは、電圧１〜３ｋＶ、周波数１ｋＨｚ、パルス幅５マイクロ秒、負パルスは、電圧２０ｋＶ、周波数０．５〜２ｋＨｚ、パルス幅２〜１０マイクロ秒、処理時間は約３０分が例示される。しかし、これらの条件は、これらに制限されるものではなく、製品の種類、及び処理目的等に応じて、適宜、変更することができる。
【００１３】
次に、高導電性の非晶質窒化炭素膜の形成のための条件は、好適には、例えば、ガス条件として、ガス種はトルエン及び窒素ガス、ガス流量は、それぞれ、２〜４ｓｃｃｍ、３〜１０ｓｃｃｍ、真空度（プロセス時）は２〜４×１０−４Ｔｏｒｒ程度、パルス印加条件として、正パルスは、電圧３〜６ｋＶ、周波数１〜３ｋＨｚ、パルス幅２〜１０マイクロ秒、負パルスは、電圧１〜２０ｋＶ、周波数０．５〜３ｋＨｚ、パルス幅５マイクロ秒、処理時間は約３０分が例示される。しかし、これらの条件は、これらに制限されるものではなく、製品の種類、及び処理目的等に応じて、適宜、変更することができる。また、本発明では、プラズマ点火を容易にするために、高周波電源を用いて高周波放電（例えば、１３．５６ＭＨｚ）を行うことができる。
【００１４】
本発明で使用される装置の一例を、図１に示す。本発明では、例えば、図１に示されるように、試料容器１（真空槽）、真空ポンプ２、メタン、炭化水素化合物及び窒素３、ガス流量計４、高周波電源５、メインバルブ６、高電圧パルス電源７、電流導入端子８、試料９（基材）、熱電対温度計、制御ユニット、及びパソコンから構成される装置が用いられる。この場合、高周波プラズマを用いない場合は、高周波電源５を省略することができる。しかし、これらに制限されるものではなく、同効の機能を有する手段及び装置であれば同様に使用することができる。
【００１５】
次に、まず、前処理（ミキシング層形成）工程について説明する。試料容器１を真空ポンプ２を用いて、例えば、１×１０-4Ｔｏｒｒ以下まで排気した後、メタンガス３をガス流量計４を通して試料容器に導入し、高周波電源５の電源を入れ、試料容器のガス圧を、例えば、３×１０-2Ｔｏｒｒ程度に真空ポンプ２のメインバルブ６を用いて調整する。メタンプラズマが点火した段階で、試料容器１のガス圧が、例えば、５×１０-4Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を用いて調整し、高電圧パルス電源７の電源を入れ、電流導入端子８を通して負パルス電圧を試料９（基材）に印加する。これにより、メタンイオンによって試料表面は照射され、イオン注入によるミキシング層の形成が行われる。
【００１６】
次に、非晶質窒化炭素膜の堆積工程について説明する。トルエン等の炭化水素ガス及び窒素ガス３をガス流量計４を通して試料容器に導入し、高周波電源の電源を入れ、試料容器のガス圧が、例えば、５×１０-2Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を用いて調整する。ガスプラズマが点火した段階で、高電圧パルス電源７の電源を入れ、試料容器のガス圧を、例えば、２×１０-4Ｔｏｒｒ程度に真空ポンプ２のメインバルブ６を用いて調整し、高電圧パルス電源７の正パルス電圧、負パルス電圧を試料１に印加する。これにより、試料（基材）表面にプラズマ電子による照射と、炭化水素及び窒素のラジカルの堆積とイオン照射がなされる。図２に基材に印加するパルス電圧、及びこれらのパルスによって基材に流れるパルス電流についてオシロスコープで測定した例を示す。
【００１７】
次に、本発明の方法により作製された高導電性非晶質窒化炭素膜の特性について具体的に説明する。尚、ここでは、後記する実施例１に記載の方法と同様の方法で作製した非晶質窒化炭素膜について、その特性を測定した試験例を示す。
試験例
（１）耐食性試験
５％硫酸溶液について、耐食性試験（アノード分極測定）を行った。図３に、その結果を示す。図中、Ｎｏ．１は、未処理のＳＵＳ３０４について、Ｎｏ．２は、正パルスバイアスなしで作製した非晶質炭素（ＤＬＣ）膜コーティング試料について、Ｎｏ．３は、非晶質窒化炭素コーティングした試料についての分極特性である。１〜１．５Ｖのあたりで、３桁近くアノード電流密度が減少しており、ＤＬＣに比べて耐食特性が向上していることが分かった。
【００１８】
（２）接触抵抗測定
接触抵抗は、基板試料に断面積０．５ｃｍ2 のＣｕ電極を一定圧力（１０ｋｇｆ）でプレスし、この両電極間の電気抵抗を測定して調べた。基板試料として、ＳＵＳ３０４に非晶質窒化炭素膜を膜厚０．２μｍで形成したものを用いた。表１に、正パルス電圧に依存する接触抵抗値を示す。尚、比較例として、窒素ガスを導入しない場合に形成されるＤＬＣ膜の値を表１に示す。

Figure 0004150789
以上の結果から、本発明に係る非晶質窒化炭素膜は、ＤＬＣ膜に比べて、接触抵抗が下がることが確認された。
【００１９】
（３）電気抵抗測定
窒化炭素膜の電気抵抗率を４端子測定法により測定した。試料はいずれも０．２ミクロン厚さの窒化炭素をステンレス板（ＳＵＳ３０４）にコーティングしたものを用いた。
電気抵抗率の正パルス電圧依存性及び成膜時の基材温度の値を表２に示す。
Figure 0004150789
基材温度は、試料ホルダーに埋め込んだ熱電対温度計を用いて基材（０．１ｍｍ厚さ）の裏面から測定した。電気抵抗率が正パルス電圧４．５ｋＶ以上で著しく減少していることが分かる。また、その時の基材温度も３００℃以下である。
【００２０】
（４）窒化炭素膜組成の測定（ＲＢＳ法）
窒化炭素膜の窒素と炭素の組成比を求めるために、１．８ＭｅＶＨｅイオンによるＲＢＳ法により、本方法を用いてカーボン基材上に作製した窒化炭素膜について測定した例を図４に示した。このスペクトルを解析することによって、Ｃ：Ｎ＝８８：１２であることが分かった。
【００２１】
（５）窒化炭素膜組成の測定（ＥＲＤ法）
窒化炭素に含まれる水素の量を測定するために、２．８ＭｅＶＨｅイオンによるＥＲＤ法により、本方法を用いてＳｉ基板上に作製した膜について測定した例を図５に示す。このスペクトルを解析することによって、この場合、窒化炭素膜中の水素の量 Ｈ／（Ｃ＋Ｎ）＝０．１９であることが分かった。
【００２２】
（６）Ｘ線回折（ＧＸＲＤ法）
薄膜Ｘ線回折装置を用いてＸ線入射角度１度で、Ｓｉ単結晶上に本発明の方法を用いて作製した窒化炭素膜についてＸ線回折測定を行った。その結果、図６に示されるように、どのようなピークも認められなかったことから、得られた窒化炭素膜は非晶質であることが確認された。
【００２３】
（７）微小硬度測定
得られた窒化炭素膜について、ナノインデンターの圧子の押し込み深さと荷重の関係から、膜の微少硬度を測定した。膜の硬度は、１１．９３Ｇｐａであり、通常の正パルスを用いない方法で作製した窒化炭素膜よりは幾分柔らかいが、金属よりはるかに高硬度であった。
【００２４】
【作用】
本発明では、メタンガスプラズマによるミキシングによる前処理を行うが、メタンプラズマ中に基材を浸し、基材に負高電圧パルスを印加することによって、プラズマ中の正イオンを基材に全方向から照射し、それにより、電気導電性のミキシング層を形成する。次に、トルエンなど分子量の大きい炭化水素及び窒素ガスを真空槽に導入し、高周波放電、グロー放電などによって、これらのプラズマを生成しラジカルを基材表面に堆積させるとともに、基材に負電圧を印加し、正イオンを基材に照射する。この際に、正高電圧パルスを基材に印加し、プラズマ中の電子を基材に照射することによって、表層のみをパルス的に活性化、及び高温状態にするとともに、基材の温度上昇を炭化水素及び窒素のラジカルを堆積させイオン照射を行う。ちなみに、４ｋｅＶ電子の炭素中の飛程は、およそ０．１〜０．２ミクロンであり、ほとんど基材に達しないため、基材の温度上昇を防ぐことができる。これまで非晶質炭素膜内に取り込まれた窒素原子は、ｎ型ドナーとして振る舞い、ドナー準位に束縛されていた電子が、効果的に伝導帯に励起されて、電気導電性が増すと考えられており、本発明の方法で作製した窒化炭素膜は、膜形成時に電子照射によりパルス的に高温状態にしていることから、効率的に窒素原子が非晶質炭素膜内にドープされるとともに、更に炭素原子間においては高温で堆積させているためグラファイト構造が優勢であることが予想されることなどから電気導電率が増加したものと考えることができる。
【００２５】
【実施例】
次に、実施例に基づいて本発明を具体的に説明するが、本発明は、以下の実施例によって何ら限定されるものではない。
実施例１
本実施例では、図１の装置を用いて、ＳＵＳにカーボン膜を形成した。
（１）前処理（ミキシング層形成）
試料容器１を、真空ポンプ２を用いて、１×１０-4Ｔｏｒｒ以下まで排気した。次に、メタンガス（ＣＨ4 ）３を、ガス流量計４を通して７ｓｃｃｍの流量で試料容器に導入した。次いで、高周波電源５の電源をＯＮにし、試料容器のガス圧力が、おおよそ３×１０-2Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を調整した。メタンガスプラズマが点火し、そこで、試料容器１のガス圧力が５×１０-4Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を調整した。高電圧パルス電源７をＯＮにし、電流導入端子８を通して、負パルス電圧（−２０ｋＶ、１ｋＨｚ）を試料９に印加した。これにより、メタンイオンによって試料表面は照射され、イオン注入によるミキシング層が形成された。３０分後、高電圧パルス電源７、及び高周波電源５をＯＦＦにし、メタンガスの供給を止めると共に、真空ポンプ２のメインバルブ６を完全に開き、試料容器１を排気した。
【００２６】
（２）非晶質窒化炭素膜の堆積
次に、炭化水素ガス（ＣｘＨｙ）としてのトルエン（Ｃ7 Ｈ8 ）と窒素ガス３をガス流量計４を通して、それぞれ、２ｓｃｃｍ、５ｓｃｃｍの流量で試料容器に導入した。高周波電源をＯＮにし、試料容器のガス圧力が、おおよそ５×１０-2Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を調整した。ガスプラズマが点火し、そこで、高電圧パルス電源７をＯＮにし、試料容器１のガス圧力が２×１０-4Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を調整した。高電圧パルス電源７の正パルス電圧（３〜６ｋＶ、２〜３ｋＨｚ）、負パルス電圧（１〜２０ｋＶ、２〜３ｋＨｚ）を試料１に印加した。これにより、基材表面にプラズマ電子による照射、及び炭化水素イオン及び窒素イオンが堆積された。適当な時間（１５分〜２時間）の後、高電圧パルス電源７、及び高周波電源５をＯＦＦにし、ガスの供給をとめた。
【００２７】
実施例２
（１）前処理（ミキシング層形成）
本実施例では、図１の装置を用いて、基材に、高導電性非晶質窒化炭素膜を形成した。試料容器１を、真空ポンプ２を用いて、１×１０-4Ｔｏｒｒ以下まで排気した。次に、メタンガス（ＣＨ4 ）３を、ガス流量計４を通して７ｓｃｃｍの流量で試料容器１に導入した。次いで、高電圧パルス電源７の電源をＯＮにし、正パルス（約２〜３ｋＶ、１ｋＨｚ）を電流導入端子８を通して試料９に供給した。試料容器１のガス圧力が、おおよそ３×１０-2Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を調整した。メタンガスプラズマを点火し、試料容器１のガス圧力が５×１０-4Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を調整した。次いで、高電圧パルス電源７から、負パルス電圧（−２０ｋＶ、１ｋＨｚ）を試料９に印加した。これにより、メタンイオンによって試料表面は照射され、イオン注入によるミキシング層が形成された。３０分後、高電圧パルス電源７をＯＦＦにし、メタンガスの供給を止めると共に、真空ポンプ２のメインバルブ６を完全に開き、試料容器１を排気した。
【００２８】
（２）非晶質窒化炭素膜の堆積
次に、炭化水素ガス（ＣｘＨｙ）としてのトルエン（Ｃ7 Ｈ8 ）と窒素ガスをガス流量計４を通して、２ｓｃｃｍ、５ｓｃｃｍの流量で試料容器１に導入した。高電圧パルス電源７の電源をＯＮにし、正パルス（約２〜３ｋＶ、２ｋＨｚ）を電流導入端子８を通して試料１に供給した。試料容器１のガス圧力が、おおよそ５×１０-2Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を調整した。その結果、ガスプラズマが点火し、そこで、高電圧パルス電源７をＯＮにし、試料容器１のガス圧力が２×１０-4Ｔｏｒｒ程度になるように真空ポンプ２のメインバルブ６を調整した。次に、高電圧パルス電源から正パルス電圧（３〜６ｋＶ、２〜３ｋＨｚ）、負パルス電圧（１〜２０ｋＶ、２〜３ｋＨｚ）を試料１に印加した。これにより、基材表面にプラズマ電子による照射、及び炭化水素イオンと窒素イオンの堆積が起こった。適当な時間（１５分〜２時間）の後、高電圧パルス電源７をＯＦＦにし、ガスの供給を止めた。
【００２９】
【発明の効果】
以上詳述したように、本発明は、非晶質窒化炭素膜の形成方法、及び非晶質窒化炭素膜−基材複合体の製造方法に係るものであり、本発明により、１）低温（３００℃以下）で優れた非晶質窒化炭素膜を製造できる、２）金属製基材との密着性に優れた非晶質窒化炭素薄膜を製造できる、３）溝加工を施した（複雑形状の）金属薄板上へ、高密着性、高電気導電性、高耐食性の非晶質窒化炭素膜をコーティングする方法を提供できる、４）燃料電池セパレート板、スイッチ接点などの複雑形状をした部材に有用な非晶質窒化炭素膜−基材複合体を提供できる、５）それらの製品を提供できる、という格別の効果が奏される。
【図面の簡単な説明】
【図１】非晶質窒化炭素膜形成装置を示す。
【図２】パルス波形の例を示す。
【図３】耐食性試験によるアノード分極測定の結果を示す。
【図４】非晶質窒化炭素膜の組成（窒素／炭素）をＲＢＳ法で測定した結果を示す。
【図５】非晶質窒化炭素膜中の水素量をＥＲＤ法で測定した結果を示す。
【図６】非晶質窒化炭素膜の薄膜Ｘ線回折装置を用いて測定したＸ線回折図を示す。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming an amorphous carbon nitride film, and a method for producing an amorphous carbon nitride film-base material composite, and more particularly, to an electrical conductivity, corrosion resistance, and adhesion to a base material. The present invention relates to a method for producing a highly conductive amorphous carbon nitride film-substrate composite formed by forming an amorphous carbon nitride film having excellent properties, and a composite produced by the method. The present invention relates to a method for forming an amorphous carbon nitride film having high conductivity, high corrosion resistance, and high adhesion on a conductive substrate having a complicated shape such as a fuel cell separator, various electrodes, switch contacts, and the like, and It is useful for providing the product.
[0002]
[Prior art]
Conventionally, for example, as a material for a separator (bipolar plate) of a fuel cell, an electrolyte membrane is strongly acidic, and good conductivity is required. Therefore, in many cases, a gas-impermeable carbon plate is used. It is used. The surface is subjected to groove processing for forming a gas flow path. Conventionally, as this material, a plate cut out from a lump of graphite was used, but in order to reduce costs, resin-molded carbon that does not require labor-intensive machining, and gas impermeable to expanded graphite base material A method for forming grooves and manifolds by pressure molding of porous carbon films, and a method for forming a carbon / carbon composite material by adding resin or pitch to carbon, molding, firing / carbonizing, etc. are being studied. . In addition, metals such as titanium and stainless steel, and composite materials of metal and carbon have been studied.
[0003]
However, when a metal is used as a material for a fuel cell, its surface tends to be corroded and the contact resistance tends to increase. Therefore, measures such as plating the surface with a noble metal are required. A method of coating an amorphous carbon (DLC) film on a metal material such as stainless steel has also been proposed. Examples of methods for coating these materials on the substrate include sputtering, electron beam vapor deposition, and carbon coating. However, none of these methods can be used because of insufficient adhesion, wearability, and electrical conductivity. There is a problem that. Further, the method of carbonizing an amorphous carbon film at a high temperature has a problem that the base material needs to be heated to 800 ° C. or more and cannot be applied due to thermal deformation of the base material. On the other hand, for example, in a fuel cell separate plate, a technique for coating a carbon material having excellent electrical conductivity and corrosion resistance on a metal thin plate having a complicated shape having grooves and the like is required.
[0004]
Conventionally, as a method and apparatus for producing an amorphous carbon nitride film, for example, a method using laser ablation (see Patent Document 1), a method using a pinch plasma of a graphite electrode and nitrogen gas (see Patent Document 2), plasma, A method using a chemical vapor deposition method and an ion beam deposition method (see Patent Document 3), a method using a combination of carbon vapor and a nitrogen ion beam (see Patent Document 4), a method using high-frequency magnetron sputtering (Patent Document 5) Etc.) are proposed. However, these prior arts, for example, further improve in terms of electrical conductivity, corrosion resistance and adhesion, and develop a method for forming a highly conductive coating film at a low temperature (base temperature of 300 ° C. or lower). Was strongly requested. However, these prior arts have not yet been put into practical use in terms of, for example, electrical conductivity and adhesion, and in this technical field, further improvements are made in terms of electrical conductivity, corrosion resistance, and adhesion. In addition, there has been a strong demand to develop a method for forming a highly conductive film of an amorphous carbon film at a low temperature (300 ° C. or lower).
[0005]
[Patent Document 1]
JP 11-229124 A [Patent Document 2]
JP 2001-59156 A [Patent Document 3]
JP 2000-285437 A [Patent Document 4]
JP-A-11-209868 [Patent Document 5]
Japanese Patent Laid-Open No. 11-238684
[Problems to be solved by the invention]
Under such circumstances, the present inventors have conducted intensive research with the goal of developing a new technology that can drastically solve the problems of the conventional technology in view of the conventional technology. As a result of the stacking, the process of forming the mixing layer on the surface of the substrate, the generation of plasma of hydrocarbons and nitrogen and the step of irradiating the substrate with positive ions, and the application of high voltage positive pulses to the substrate and the electrons in the plasma To find out that an amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance and adhesion can be formed by adjusting the treatment conditions by combining the irradiation process to the substrate, and to complete the present invention It came.
[0007]
An object of the present invention is to provide a method for forming an amorphous carbon nitride thin film having excellent electrical conductivity (contact resistance of 10 mΩ / cm 2 or less) at a low temperature (300 ° C. or less) on a substrate. It is.
Another object of the present invention is to provide a method for producing an amorphous carbon nitride thin film having excellent adhesion to a metal substrate.
In addition, the present invention provides a method for coating an amorphous carbon nitride film having high adhesion, high electrical conductivity, and high corrosion resistance on a (complex shape) thin metal plate subjected to groove processing such as a fuel cell separator. It is intended to provide.
Another object of the present invention is to provide a method for efficiently producing an amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance and adhesion on a substrate having a complicated shape at low cost. It is.
[0008]
[Means for Solving the Problems]
The present invention for solving the above-described problems comprises the following technical means.
(1) A method of forming an amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance and adhesion on a conductive substrate,
(A) Immerse the substrate in methane gas plasma in a vacuum chamber, irradiate the substrate with positive ions in the plasma, and form a mixing layer by ion implantation on the surface layer.
(B) A mixed gas of hydrocarbon and nitrogen is introduced into a vacuum chamber, plasma is generated, these radicals are deposited on the surface of the base material, a negative voltage is applied to the base material, and positive ions are accelerated. Irradiate the substrate,
(C) In that case, a positive high voltage pulse (preferably 3 to 15 kV) is applied to the substrate, and electrons in the plasma are irradiated to the substrate with high energy, whereby only the surface layer is activated in a pulsed manner. And high temperature,
(D) According to the above (a) to (c), hydrocarbons and nitrogen radicals and ions are deposited on a substrate at 140 ° C. or higher and at 300 ° C. or lower, and the conflict resistance is 10 mΩ / cm 2 or A highly conductive amorphous carbon nitride film having a smaller value and an electrical resistivity of less than 1 kΩ · cm is formed.
A method for forming an amorphous carbon nitride film.
(2) A method for producing a highly conductive amorphous carbon nitride film-substrate composite formed by forming an amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance and adhesion on a conductive substrate. There,
(A) Immerse the substrate in methane gas plasma in a vacuum chamber, irradiate the substrate with positive ions in the plasma, and form an ion implantation layer on the surface layer.
(B) A mixed gas of hydrocarbon and nitrogen is introduced into a vacuum chamber, plasma is generated, these radicals are deposited on the surface of the base material, a negative voltage is applied to the base material, and positive ions are accelerated. Irradiate the substrate,
(C) At that time, a high voltage positive pulse is applied to the substrate, and electrons in the plasma are irradiated to the substrate with high energy, whereby only the surface layer is activated in a pulsed manner and brought to a high temperature state.
(D) According to the above (a) to (c), hydrocarbons and nitrogen radicals and ions are deposited on a substrate at a temperature higher than 140 ° C. and lower than 300 ° C., and the resistance to conflict is 10 mΩ / cm 2 or less. And producing a highly conductive amorphous carbon nitride film-substrate composite formed with a highly conductive amorphous carbon nitride film having an electrical resistivity of less than 1 kΩ · cm .
A method for producing a highly conductive amorphous carbon nitride film-base material composite.
(3) The method according to (1) or (2) above, wherein the substrate is a thin metal plate having a complicated shape.
(4) The method according to (3) above, wherein the substrate is an electrode having a complicated shape.
(5) The method according to (3), wherein the substrate is a switch contact having a complicated shape.
(6) An amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance and adhesion is deposited on a base material produced by the method according to any one of (2) to (5), A highly conductive amorphous carbon nitride film-substrate composite having a resistance value of 10 mΩ / cm 2 or less and an electric resistivity of less than 1 kΩ · cm .
(7) A highly conductive member for electrode or switch contact comprising the composite according to (6) as a constituent element.
(8) The highly conductive member according to (7) above, which is a fuel cell separator.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the present invention mainly comprises a highly conductive amorphous carbon nitride film-substrate formed by forming an amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance and adhesion on a substrate. A method for producing a composite, comprising: (a) immersing a substrate in methane gas plasma in a vacuum chamber, irradiating the substrate with positive ions in the plasma, and forming an ion implantation layer on the surface layer; (b) carbonization A mixed gas of hydrogen and nitrogen is introduced into a vacuum chamber, plasma is generated, these radicals are deposited on the substrate, a negative voltage is applied to the substrate, and positive ions are accelerated to irradiate the substrate. (C) At that time, a positive high voltage pulse is applied to the substrate, and the substrate is irradiated with electrons in the plasma, whereby only the surface layer is activated in a pulsed manner and brought to a high temperature state. (D) Deposition of hydrocarbon and nitrogen radicals and ions on the substrate by (a) to (c) So, highly conductive amorphous carbon nitride film formed amorphous carbon nitride film of highly conductive - producing substrate complex, it is characterized in.
[0010]
In the present invention, first, a negative high voltage pulse is applied to a substrate placed in methane plasma to irradiate methane ions from all directions of the substrate, and a conductive film in which carbon atoms are dispersed by ion implantation. Form. Next, hydrocarbons with high molecular weight such as toluene and nitrogen gas are simultaneously introduced into the vacuum chamber, these plasmas are generated by high frequency discharge, glow discharge, etc., a negative voltage is applied to the substrate, and positive ions are applied. To the substrate. At this time, by applying a high voltage positive pulse to the substrate and irradiating the substrate with electrons in the plasma, only the surface layer is activated in a pulsed manner, and the temperature of the substrate is raised. Instead, deposit hydrocarbon and nitrogen plasma. In the present invention, by combining these steps organically, for example, an amorphous carbon nitride film having high conductivity, high corrosion resistance, and high adhesion can be formed on a substrate having a complicated shape.
[0011]
In the present invention, plasma can be preferably generated by, for example, pulsed plasma generation by glow discharge, radio frequency discharge (RF), electron cyclotron resonance (ECR) discharge, or a combination thereof. Any method and apparatus can be used without limitation. In the present invention, a film is formed by deposition (deposition) of amorphous carbon using ions generated by plasma discharge of the hydrocarbon compound CxHy. As the hydrocarbon compound CxHy, x = 1 to 10, y = 2 to 22 hydrocarbons are preferably used.
[0012]
In the present invention, the conditions for forming the ion implantation layer on the surface layer by carbon ions from methane gas plasma are preferably, for example, as the gas condition, the gas type is methane, the gas flow rate is 5 to 10 sccm, and the degree of vacuum ( (Process time) is about 2 to 5 × 10 −4 Torr, pulse application conditions are as follows: positive pulse: voltage 1 to 3 kV, frequency 1 kHz, pulse width 5 microseconds, negative pulse: voltage 20 kV, frequency 0.5 to 2 kHz The pulse width is 2 to 10 microseconds, and the processing time is about 30 minutes. However, these conditions are not limited to these, and can be appropriately changed according to the type of product, the purpose of processing, and the like.
[0013]
Next, the conditions for the formation of the highly conductive amorphous carbon nitride film are preferably, for example, as gas conditions, gas types are toluene and nitrogen gas, and gas flow rates are 2 to 4 sccm, 3 respectively. ～10Sccm, vacuum (when the process) is 2 to 4 × 10 -4 Torr or so, as the pulse applying condition, the positive pulse voltage 3 ～6KV, frequency 1～3KHz, pulse width 2-10 microseconds, negative pulses The voltage is 1 to 20 kV, the frequency is 0.5 to 3 kHz, the pulse width is 5 microseconds, and the processing time is about 30 minutes. However, these conditions are not limited to these, and can be appropriately changed according to the type of product, the purpose of processing, and the like. In the present invention, in order to facilitate plasma ignition, high frequency discharge (for example, 13.56 MHz) can be performed using a high frequency power source.
[0014]
An example of an apparatus used in the present invention is shown in FIG. In the present invention, for example, as shown in FIG. 1, a sample container 1 (vacuum tank), a vacuum pump 2, methane, hydrocarbon compounds and nitrogen 3, a gas flow meter 4, a high-frequency power source 5, a main valve 6, a high voltage An apparatus including a pulse power source 7, a current introduction terminal 8, a sample 9 (base material), a thermocouple thermometer, a control unit, and a personal computer is used. In this case, when the high frequency plasma is not used, the high frequency power source 5 can be omitted. However, the present invention is not limited to these, and any means and device having the same function can be used in the same manner.
[0015]
Next, a pretreatment (mixing layer formation) step will be described first. After the sample container 1 is evacuated to, for example, 1 × 10 −4 Torr or less using the vacuum pump 2, the methane gas 3 is introduced into the sample container through the gas flow meter 4, the high frequency power supply 5 is turned on, and the sample container is For example, the gas pressure is adjusted to about 3 × 10 −2 Torr using the main valve 6 of the vacuum pump 2. When the methane plasma is ignited, the gas pressure in the sample container 1 is adjusted by using the main valve 6 of the vacuum pump 2 so that the gas pressure in the sample container 1 becomes about 5 × 10 −4 Torr, for example, and the power source of the high voltage pulse power source 7 is turned on. The negative pulse voltage is applied to the sample 9 (base material) through the current introduction terminal 8. As a result, the sample surface is irradiated with methane ions, and a mixing layer is formed by ion implantation.
[0016]
Next, the deposition process of the amorphous carbon nitride film will be described. A hydrocarbon gas such as toluene and nitrogen gas 3 are introduced into the sample container through the gas flow meter 4, the high frequency power supply is turned on, and the sample container is evacuated so that the gas pressure is, for example, about 5 × 10 −2 Torr. Adjustment is performed using the main valve 6 of the pump 2. When the gas plasma is ignited, the high-voltage pulse power supply 7 is turned on, and the gas pressure in the sample container is adjusted to about 2 × 10 −4 Torr using the main valve 6 of the vacuum pump 2, for example. A positive pulse voltage and a negative pulse voltage of the pulse power source 7 are applied to the sample 1. As a result, irradiation with plasma electrons, deposition of hydrocarbon and nitrogen radicals, and ion irradiation are performed on the surface of the sample (base material). FIG. 2 shows an example in which the pulse voltage applied to the substrate and the pulse current flowing through the substrate by these pulses are measured with an oscilloscope.
[0017]
Next, the characteristics of the highly conductive amorphous carbon nitride film produced by the method of the present invention will be specifically described. Here, a test example is shown in which the characteristics of an amorphous carbon nitride film manufactured by a method similar to the method described in Example 1 described later are measured.
Test Example (1) Corrosion Resistance Test A 5% sulfuric acid solution was subjected to a corrosion resistance test (anodic polarization measurement). FIG. 3 shows the result. In the figure, No. No. 1 is the No. 1 for unprocessed SUS304. No. 2 shows an amorphous carbon (DLC) film-coated sample prepared without a positive pulse bias. 3 is a polarization characteristic of the sample coated with amorphous carbon nitride. Around 1 to 1.5 V, the anode current density was reduced by almost three orders of magnitude, indicating that the corrosion resistance was improved compared to DLC.
[0018]
(2) Contact resistance measurement Contact resistance was examined by pressing a Cu electrode having a cross-sectional area of 0.5 cm 2 on a substrate sample at a constant pressure (10 kgf) and measuring the electrical resistance between the two electrodes. As a substrate sample, an SUS304 formed with an amorphous carbon nitride film with a film thickness of 0.2 μm was used. Table 1 shows the contact resistance values depending on the positive pulse voltage. As a comparative example, Table 1 shows values of a DLC film formed when nitrogen gas is not introduced.
Figure 0004150789
From the above results, it was confirmed that the amorphous carbon nitride film according to the present invention has a lower contact resistance than the DLC film.
[0019]
(3) Electrical resistance measurement The electrical resistivity of the carbon nitride film was measured by a 4-terminal measurement method. All samples used were carbon nitride having a thickness of 0.2 microns coated on a stainless steel plate (SUS304).
Table 2 shows the positive pulse voltage dependency of the electrical resistivity and the substrate temperature during film formation.
Figure 0004150789
The substrate temperature was measured from the back surface of the substrate (0.1 mm thickness) using a thermocouple thermometer embedded in the sample holder. It can be seen that the electrical resistivity is remarkably reduced at a positive pulse voltage of 4.5 kV or more. Further, the substrate temperature at that time is also 300 ° C. or less.
[0020]
(4) Measurement of carbon nitride film composition (RBS method)
FIG. 4 shows an example in which the carbon nitride film produced on the carbon substrate using this method was measured by the RBS method using 1.8 MeVHe ions in order to obtain the composition ratio of nitrogen and carbon in the carbon nitride film. By analyzing this spectrum, it was found that C: N = 88: 12.
[0021]
(5) Measurement of carbon nitride film composition (ERD method)
In order to measure the amount of hydrogen contained in carbon nitride, FIG. 5 shows an example in which a film formed on a Si substrate using this method is measured by ERD method using 2.8 MeVHe ions. By analyzing this spectrum, it was found that in this case, the amount of hydrogen in the carbon nitride film H / (C + N) = 0.19.
[0022]
(6) X-ray diffraction (GXRD method)
X-ray diffraction measurement was performed on a carbon nitride film produced by using the method of the present invention on a Si single crystal at an X-ray incident angle of 1 degree using a thin film X-ray diffractometer. As a result, as shown in FIG. 6, since no peak was observed, it was confirmed that the obtained carbon nitride film was amorphous.
[0023]
(7) Measurement of microhardness With respect to the obtained carbon nitride film, the microhardness of the film was measured from the relationship between the indentation depth of the nanoindenter and the load. The hardness of the film was 11.93 Gpa, which was somewhat softer than the carbon nitride film produced by a method not using a normal positive pulse, but much harder than metal.
[0024]
[Action]
In the present invention, pretreatment is performed by mixing with methane gas plasma. By immersing the substrate in methane plasma and applying a negative high voltage pulse to the substrate, positive ions in the plasma are irradiated to the substrate from all directions. Thus, an electrically conductive mixing layer is formed. Next, hydrocarbons with high molecular weight, such as toluene, and nitrogen gas are introduced into the vacuum chamber, and these plasmas are generated by high-frequency discharge, glow discharge, etc., and radicals are deposited on the substrate surface, and a negative voltage is applied to the substrate. The substrate is irradiated with positive ions. At this time, by applying a positive high voltage pulse to the substrate and irradiating the substrate with electrons in the plasma, only the surface layer is activated in a pulsed manner and brought to a high temperature state, and the temperature rise of the substrate is carbonized. Ions are irradiated by depositing hydrogen and nitrogen radicals. By the way, the range of 4 keV electrons in carbon is about 0.1 to 0.2 microns, and hardly reaches the substrate, so that the temperature rise of the substrate can be prevented. Nitrogen atoms previously incorporated into amorphous carbon films behave as n-type donors, and electrons bound to the donor level are effectively excited to the conduction band, increasing the electrical conductivity. The carbon nitride film produced by the method of the present invention is pulsed at a high temperature by electron irradiation at the time of film formation, so that nitrogen atoms are efficiently doped into the amorphous carbon film. Furthermore, it can be considered that the electrical conductivity has increased because the graphite structure is expected to dominate because carbon atoms are deposited at a high temperature.
[0025]
【Example】
EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.
Example 1
In this example, a carbon film was formed on SUS using the apparatus shown in FIG.
(1) Pretreatment (mixing layer formation)
The sample container 1 was evacuated to 1 × 10 −4 Torr or less using the vacuum pump 2. Next, methane gas (CH 4 ) 3 was introduced into the sample container through the gas flow meter 4 at a flow rate of 7 sccm. Next, the power source of the high-frequency power source 5 was turned on, and the main valve 6 of the vacuum pump 2 was adjusted so that the gas pressure in the sample container was about 3 × 10 −2 Torr. The methane gas plasma was ignited, and the main valve 6 of the vacuum pump 2 was adjusted so that the gas pressure in the sample container 1 was about 5 × 10 −4 Torr. The high voltage pulse power supply 7 was turned on, and a negative pulse voltage (−20 kV, 1 kHz) was applied to the sample 9 through the current introduction terminal 8. Thereby, the sample surface was irradiated with methane ions, and a mixing layer was formed by ion implantation. After 30 minutes, the high-voltage pulse power supply 7 and the high-frequency power supply 5 were turned off, the supply of methane gas was stopped, the main valve 6 of the vacuum pump 2 was completely opened, and the sample container 1 was evacuated.
[0026]
(2) Deposition of amorphous carbon nitride film Next, toluene (C 7 H 8 ) as a hydrocarbon gas (CxHy) and nitrogen gas 3 are passed through a gas flow meter 4 at a flow rate of 2 sccm and 5 sccm, respectively. Introduced. The high frequency power supply was turned on, and the main valve 6 of the vacuum pump 2 was adjusted so that the gas pressure in the sample container was about 5 × 10 −2 Torr. The gas plasma was ignited. Therefore, the high voltage pulse power source 7 was turned on, and the main valve 6 of the vacuum pump 2 was adjusted so that the gas pressure in the sample container 1 was about 2 × 10 −4 Torr. A positive pulse voltage (3 to 6 kV, 2 to 3 kHz) and a negative pulse voltage (1 to 20 kV, 2 to 3 kHz) of the high voltage pulse power source 7 were applied to the sample 1. Thereby, irradiation with plasma electrons, and hydrocarbon ions and nitrogen ions were deposited on the surface of the substrate. After an appropriate time (15 minutes to 2 hours), the high voltage pulse power source 7 and the high frequency power source 5 were turned off, and the gas supply was stopped.
[0027]
Example 2
(1) Pretreatment (mixing layer formation)
In this example, a highly conductive amorphous carbon nitride film was formed on a substrate using the apparatus of FIG. The sample container 1 was evacuated to 1 × 10 −4 Torr or less using the vacuum pump 2. Next, methane gas (CH 4 ) 3 was introduced into the sample container 1 through the gas flow meter 4 at a flow rate of 7 sccm. Next, the power source of the high voltage pulse power source 7 was turned on, and a positive pulse (about 2 to 3 kV, 1 kHz) was supplied to the sample 9 through the current introduction terminal 8. The main valve 6 of the vacuum pump 2 was adjusted so that the gas pressure in the sample container 1 was about 3 × 10 −2 Torr. Methane gas plasma was ignited, and the main valve 6 of the vacuum pump 2 was adjusted so that the gas pressure in the sample container 1 was about 5 × 10 −4 Torr. Next, a negative pulse voltage (−20 kV, 1 kHz) was applied to the sample 9 from the high voltage pulse power source 7. Thereby, the sample surface was irradiated with methane ions, and a mixing layer was formed by ion implantation. After 30 minutes, the high-voltage pulse power supply 7 was turned off, the supply of methane gas was stopped, the main valve 6 of the vacuum pump 2 was completely opened, and the sample container 1 was evacuated.
[0028]
(2) Deposition of amorphous carbon nitride film Next, toluene (C 7 H 8 ) as hydrocarbon gas (CxHy) and nitrogen gas are introduced into the sample container 1 through the gas flowmeter 4 at a flow rate of 2 sccm and 5 sccm. did. The power source of the high voltage pulse power source 7 was turned on, and a positive pulse (about 2 to 3 kV, 2 kHz) was supplied to the sample 1 through the current introduction terminal 8. The main valve 6 of the vacuum pump 2 was adjusted so that the gas pressure in the sample container 1 was about 5 × 10 −2 Torr. As a result, the gas plasma was ignited. Therefore, the high voltage pulse power source 7 was turned on, and the main valve 6 of the vacuum pump 2 was adjusted so that the gas pressure in the sample container 1 was about 2 × 10 −4 Torr. Next, a positive pulse voltage (3 to 6 kV, 2 to 3 kHz) and a negative pulse voltage (1 to 20 kV, 2 to 3 kHz) were applied to the sample 1 from a high voltage pulse power source. As a result, irradiation with plasma electrons and deposition of hydrocarbon ions and nitrogen ions occurred on the substrate surface. After an appropriate time (15 minutes to 2 hours), the high voltage pulse power source 7 was turned off and the gas supply was stopped.
[0029]
【The invention's effect】
As described above in detail, the present invention relates to a method for forming an amorphous carbon nitride film and a method for producing an amorphous carbon nitride film-base material composite. 300 ° C. or lower) can produce an excellent amorphous carbon nitride film, 2) can produce an amorphous carbon nitride thin film with excellent adhesion to a metal substrate, and 3) grooved (complex shape) 4) It is possible to provide a method for coating an amorphous carbon nitride film with high adhesion, high electrical conductivity and high corrosion resistance on a thin metal plate. 4) For a member having a complicated shape such as a fuel cell separate plate and a switch contact. It is possible to provide a useful amorphous carbon nitride film-substrate composite, and 5) it is possible to provide such products.
[Brief description of the drawings]
FIG. 1 shows an amorphous carbon nitride film forming apparatus.
FIG. 2 shows an example of a pulse waveform.
FIG. 3 shows the results of anodic polarization measurement by a corrosion resistance test.
FIG. 4 shows the result of measuring the composition (nitrogen / carbon) of an amorphous carbon nitride film by the RBS method.
FIG. 5 shows the result of measuring the amount of hydrogen in an amorphous carbon nitride film by the ERD method.
FIG. 6 shows an X-ray diffraction pattern measured using a thin film X-ray diffraction apparatus for an amorphous carbon nitride film.

Claims (8)

導電性基材に、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を形成する方法であって、
（１）真空槽で基材をメタンガスプラズマ中に浸し、プラズマ中の正イオンを基材に照射し、表層にイオン注入によるミキシング層を形成する、
（２）炭化水素と窒素の混合ガスを真空槽に導入し、プラズマを生成させ、これらのラジカルを基材表面に堆積させるとともに、基材に、負電圧を印加し、正イオンを加速して基材に照射する、
（３）その際に、少なくともパルス電圧３ｋＶ、周波数１ｋＨｚの高電圧正パルスを基材に印加し、プラズマ中の電子を高エネルギーで基材に照射することによって、表層のみをパルス的に活性化、及び高温状態にする、
（４）上記（１）〜（３）により、１４０℃又はそれより高温で３００℃又はそれより低温の基材に炭化水素及び窒素のラジカル及びイオンを堆積させ、抵触抵抗が１０ｍΩ／ｃｍ ２ 又はそれより小さい値で、電気抵抗率が１ｋΩ・ｃｍより小さい値を有する高導電性の非晶質窒化炭素膜を形成する、
ことを特徴とする非晶質窒化炭素膜の形成方法。A method of forming an amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance and adhesion on a conductive substrate,
(1) Immerse the substrate in methane gas plasma in a vacuum chamber, irradiate the substrate with positive ions in the plasma, and form a mixing layer by ion implantation on the surface layer.
(2) A mixed gas of hydrocarbon and nitrogen is introduced into a vacuum chamber, plasma is generated, these radicals are deposited on the surface of the base material, a negative voltage is applied to the base material, and positive ions are accelerated. Irradiate the substrate,
(3) At that time, by applying a high voltage positive pulse of at least a pulse voltage of 3 kV and a frequency of 1 kHz to the substrate and irradiating the substrate with electrons in the plasma with high energy, only the surface layer is activated in a pulsed manner. And high temperature
(4) According to the above (1) to (3), hydrocarbon and nitrogen radicals and ions are deposited on a substrate at 140 ° C. or higher and at 300 ° C. or lower, and the resistance to conflict is 10 mΩ / cm 2 or A highly conductive amorphous carbon nitride film having a smaller value and an electrical resistivity of less than 1 kΩ · cm is formed.
A method for forming an amorphous carbon nitride film. 導電性基材に、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を形成して成る高導電性非晶質窒化炭素膜−基材複合体を製造する方法であって、
（１）真空槽で基材をメタンガスプラズマ中に浸し、プラズマ中の正イオンを基材に照射し、表層にイオン注入層を形成する、
（２）炭化水素と窒素の混合ガスを真空槽に導入し、プラズマを生成させ、これらのラジカルを基材表面に堆積させるとともに、基材に、負電圧を印加し、正イオンを加速して基材に照射する、
（３）その際に、高電圧正パルスを基材に印加し、プラズマ中の電子を高エネルギーで基材に照射することによって、表層のみをパルス的に活性化、及び高温状態にする、
（４）上記（１）〜（３）により、１４０℃より高温で３００℃より低温の基材に炭化水素及び窒素のラジカル及びイオンを堆積させ、抵触抵抗が１０ｍΩ／ｃｍ ２ 又はそれより小さい値で、電気抵抗率が１ｋΩ・ｃｍより小さい値を有する高導電性の非晶質窒化炭素膜を形成した高導電性非晶質窒化炭素膜−基材複合体を製造する、
ことを特徴とする高導電性非晶質窒化炭素膜−基材複合体の製造方法。A method for producing a highly conductive amorphous carbon nitride film-substrate composite formed by forming an amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance and adhesion on a conductive substrate,
(1) Immerse the substrate in methane gas plasma in a vacuum chamber, irradiate the substrate with positive ions in the plasma, and form an ion implantation layer on the surface layer.
(2) A mixed gas of hydrocarbon and nitrogen is introduced into a vacuum chamber, plasma is generated, these radicals are deposited on the surface of the base material, a negative voltage is applied to the base material, and positive ions are accelerated. Irradiate the substrate,
(3) In that case, a high voltage positive pulse is applied to the substrate, and electrons in the plasma are irradiated to the substrate with high energy, so that only the surface layer is activated in a pulsed manner and brought to a high temperature state.
(4) According to the above (1) to (3), hydrocarbons and nitrogen radicals and ions are deposited on a substrate at a temperature higher than 140 ° C. and lower than 300 ° C., and the resistance to conflict is 10 mΩ / cm 2 or less. And producing a highly conductive amorphous carbon nitride film-substrate composite formed with a highly conductive amorphous carbon nitride film having an electrical resistivity of less than 1 kΩ · cm .
A method for producing a highly conductive amorphous carbon nitride film-base material composite. 基材が、複雑形状を任意に有する金属薄板である請求項１又は２記載の方法。  The method according to claim 1 or 2, wherein the substrate is a metal thin plate having an arbitrarily complex shape. 基材が、複雑形状を有する電極である請求項３記載の方法。  The method according to claim 3, wherein the substrate is an electrode having a complicated shape. 基材が、複雑形状を有するスイッチ接点である請求項３記載の方法。  4. A method according to claim 3, wherein the substrate is a switch contact having a complex shape. 請求項２から５のいずれかに記載の方法により製造された、基材に、電気導電性、耐食性及び密着性に優れた非晶質窒化炭素膜を堆積してなる、抵触抵抗が１０ｍΩ／ｃｍ ２ 又はそれより小さい値で、電気抵抗率が１ｋΩ・ｃｍより小さい値を有する高導電性非晶質窒化炭素膜−基材複合体。A contact resistance of 10 mΩ / cm, which is produced by depositing an amorphous carbon nitride film excellent in electrical conductivity, corrosion resistance, and adhesion on a base material produced by the method according to claim 2. A highly conductive amorphous carbon nitride film-substrate composite having a value of 2 or less and an electrical resistivity of less than 1 kΩ · cm . 請求項６記載の複合体を構成要素として含む電極又はスイッチ接点用高導電性部材。  A highly conductive member for electrode or switch contact comprising the composite according to claim 6 as a constituent element. 燃料電池用セパレータである請求項７記載の高導電性部材。  The highly conductive member according to claim 7, which is a fuel cell separator.
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Publication number Priority date Publication date Assignee Title
KR20070103451A (en) * 2005-02-16 2007-10-23 쓰리엠 이노베이티브 프로퍼티즈 컴파니 Fuel cell catalyst
JP4646763B2 (en) * 2005-09-28 2011-03-09 株式会社プラズマイオンアシスト Functional thin film forming method and functional thin film forming apparatus
US7740902B2 (en) 2006-04-20 2010-06-22 3M Innovative Properties Company Method for making oxygen-reducing catalyst layers
US7906251B2 (en) 2006-04-20 2011-03-15 3M Innovative Properties Company Oxygen-reducing catalyst layer
US8119242B2 (en) 2006-05-22 2012-02-21 Kabushiki Kaisha Toyota Chuo Kenkyusho Amorphous carbon film, process for forming amorphous carbon film, conductive member provided with amorphous carbon film, and fuel cell separator
CN100382367C (en) * 2006-05-26 2008-04-16 大连海事大学 Solid electrolyte membrane fuel cell metal bipolar plate containing nitrogen carbon surface and method for manufacturing same
US8497050B2 (en) * 2008-07-29 2013-07-30 GM Global Technology Operations LLC Amorphous carbon coatings for fuel cell bipolar plates
JP5289863B2 (en) * 2008-08-28 2013-09-11 東京エレクトロン株式会社 Amorphous carbon nitride film forming method, multilayer resist film, semiconductor device manufacturing method, and storage medium storing control program
US11001922B2 (en) 2011-11-17 2021-05-11 United Protective Technologies, Llc Carbon based coatings and methods of producing the same
DE102014000888B4 (en) * 2014-01-23 2017-03-09 Kevin Jablonka Josef und Danuta, als gesetzliche Vertreter des minderjährigen Jablonka Device for the catalytic, photochemical decomposition of water for the recovery of hydrogen
CN109312384B (en) 2016-06-15 2022-12-30 伊士曼化工公司 Physical vapor deposition biosensor assembly
KR102547063B1 (en) 2016-09-16 2023-06-22 이스트만 케미칼 컴파니 Biosensor electrodes fabricated by physical vapor deposition
EP3512958B1 (en) 2016-09-16 2022-04-06 Eastman Chemical Company Biosensor electrodes prepared by physical vapor deposition
US11881549B2 (en) 2017-06-22 2024-01-23 Eastman Chemical Company Physical vapor deposited electrode for electrochemical sensors

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