有機シランを用いたプラズマCVD法によるダイヤモンドライクカーボン薄膜の膜特性評価

摘要

ダイヤモンドライクカーボン（DLC）の膜特性改善のために、Si源にモノメチルシラン（MMS）を用いた高周波プラズマ化学気相成長法によりSi添加DLC（Si-DLC）膜を作製し、希釈ガスの種類や基板バイアスの方法について詳細な検討を行った。原料ガスとしてCH_4及びMMS、希釈ガスとしてAr又はH_2を使用し、基板には直流又はパルスバイアスを印加した。同じMMS/（MMS＋CH_4）流量比では直流バイアスに比べてパルスバイアスの方が膜中のSi組成［Si/（Si＋C）］が大きくなることがわかった。膜中へのSiの添加によって内部応力および摩擦係数が減少するが、パルスバイアスまたは希釈ガスにH_2を用いることで、成膜中での微粒子の発生が抑制され摩擦係数が更に減少することがわかった。%To further improve the properties of diamond-like carbon (DLC) films, we have deposited Si-incorporated DLC (Si-DLC) films by radio-frequency plasma-enhanced chemical vapor deposition using monomethylsilane (MMS) as a Si source, and investigated in detail the effects of dilution gas and substrate bias on the film properties. CH_4 and MMS gases were used to deposit Si-DLC films, and they were diluted with Ar or H_2 during deposition. A DC bias or a pulse bias applied to the substrate was used to increase the incident ion energy. The Si-DLC films deposited using the pulse bias were found to have a higher Si atomic fraction ratio [Si/(Si+C)] than the films deposited using the DC bias at identical MMS/(MMS+CH_4) ratio. The internal stress and friction coefficient decreased by the addition of Si into the films. It was found that the use of the pulse bias and/or H_2 dilution gas was effective in suppressing the formation of particles and further decreasing the friction coefficient.