Si混晶表面の酸化過程のリアルタイムXPS観察; CとGe混入効果の比較

Real-time XPS observation of oxidation processes on Si alloy surfaces; Comparison of mixing effects of C and Ge

穂積 英彬*; 加賀 利瑛*; 小川 修一*; 吉越 章隆 ; 石塚 眞治*; 寺岡 有殿; 高桑 雄二*

Hozumi, Hideaki*; Kaga, Toshihide*; Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Teraoka, Yuden; Takakuwa, Yuji*

SiGe及びSiC混晶層表面の酸化速度及び酸化反応中のGeとC原子の挙動をリアルタイムXPS測定し、両混晶層表面での酸化過程の違いについて調べた。実験はSPring-8のBL23SUの表面化学反応解析装置で行った。773Kにおける初期表面酸化速度はSi表面と比べてSiGe混晶層表面では減少し、SiC混晶層では増加した。どちらもSi原子のみが酸化され、CとGeは全く酸化されなかった。このときC原子は濃縮されて3C-SiCを形成し、Ge原子はSi基板側に拡散することが示唆された。この現象は、酸化誘起歪みによってC及びGe固溶度の増加し、酸化誘起歪みによる点欠陥発生を介してCとGe原子の拡散が起るモデルを用いて説明できる。

In order to clarify the difference of the oxidation reaction mechanism between an SiGe and SiC alloy layer, the real time photoelectron spectroscopy was employed for observing the oxidation rate and behavior of Ge and C atoms during oxidation. The experiments were performed using the surface reaction analysis apparatus placed at the BL23SU of SPring-8. By comparing between the both alloy surfaces, it is found that initial oxidation rate on the SiGe alloy was slower than that on the SiC alloy. Here, only Si atoms were oxidized on the both alloy surfaces. C atoms were condensed at SiO/Si interface and 3C-SiC alloy were formed. Ge atoms were diffused into Si substrate. These facts are resulted in the oxidation-strain-induced point-defect generation, in which C and Ge atoms are exchanged for Si atoms through the vacancies.