Rapid temperature oxidation at SiO/Si(001) interface studied by real-time X-ray photoelectron spectroscopy; Rapid cooling versus rapid heating

SiO/Si(001)界面の高速熱酸化のリアルタイム光電子分光研究; 高速冷却と高速加熱の比較

Tang, J.*; 小川 修一*; 吉越 章隆 ; 石塚 眞治*; 高桑 雄二*

Tang, J.*; Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Takakuwa, Yuji*

本研究では、Si(001)表面における急速熱酸化過程を調べるため、リアルタイムX線光電子分光法で熱誘起歪み、化学結合状態と酸化速度を同時に観察した。500Cから300Cまでの急冷却では、急昇温と同様にSiO/Si(001)界面での酸化速度が大きくなっていることが明確に示されている。これは界面歪みによってSi原子が放出され、放出Si原子やSi原子が抜けた空孔はO分子との反応及びO解離吸着反応が化学的に非常に活性化なため、酸化反応を促進すると考えた。また、界面歪み(Si, Si)の変化における点欠陥発生を考慮したRTO反応モデルを提案した。

The kinetics of rapid thermal oxidation (RTO) on Si(001) with O was investigated by real-time X-ray photoelectron spectroscopy to monitor the changes of thermal strains and oxide growth rate at the same time. We have found that rapid cooling from 500 to 100 degrees as well as the rapid heating from 300 to 500 degrees have a significant acceleration effect on the oxide growth rate at the SiO/Si(001) interface. The observed acceleration was ascribed to the defects (emitted Si atoms + vacancies) generation due to the thermal strain, which is the dissociative adsorption site of O at the SiO/Si interface. Based on the observed changes of Si and Si, a RTO reaction model is considered in terms of the oxidation-induced and thermal strains present at the SiO/Si(001) interface. In future, it is of practical importance to investigate the effect of the temperature-changing rate and temperature difference on the oxide growth acceleration.