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利用AES以及HeI(21.2eV)和同步辐射(138.5eV)光电子谱研究了H_2O在Si(100)-(2 ×1)表面上的室温吸附、高温退火效应以及开始氧化的过程.AES的测量结果表明,H_2O在这种表面上的粘附系数很大,在350K下,当曝汽量约为2L时就达到饱和,其覆盖率θ=1/2.价带区域的光电子谱出现三个由于H_2O吸附而引起的特征峰,低于价带顶分别为6.2、7.2和11.5eV.350K下的 H_2O吸附导致Si 2p能级的结合能增加0.8±0.1eV,相当于一个Si原子同一个氧原子键合的情况.在 640K下退火后,出现Si 2p的第二个化学位移峰,其位置比体内Si 2p 峰约低 1.8eV,表明这时的 H_2O已经完全离解,一部分Si原子同两个氧原子键合(可能是桥键方式). 在 870K下退火,得到Si 2p的四个化学位移峰,说明氧已经贯穿进Si的体内,形成SiO_x(x=1、2、3和4).当退火温度进一步提高到T(?)970K时,恢复Si的清洁表面,表明氧被完全脱附.
The adsorption of H 2 O on Si (100) - (2 × 1) surface, the annealing effect at high temperature and the initiation of oxidation were studied by AES, HeI (21.2 eV) and synchrotron radiation (138.5 eV) The results show that H 2 O has a large adhesion coefficient on this surface, reaching saturation at 350K with an exposure of about 2L and a coverage of θ = 1 / 2. There are three photoelectron spectra in the valence band due to H_2O adsorption characteristic peaks, lower than the top of the valence band were 6.2, 7.2 and 11.5eV H_2O adsorption at 350K led to the binding energy of Si 2p increased by 0.8 ± 0.1eV, which is equivalent to one Si atom with the same oxygen atom After annealing at 640K, a second chemical shift peak of Si 2p appeared, which was about 1.8eV lower than the Si 2p peak in the body, indicating that H 2 O had completely dissociated at this time and some of the Si atoms were identical to two oxygen At the 870K annealing, the four chemical shift peaks of Si 2p were obtained, indicating that oxygen had penetrated the Si body to form SiO x (x = 1, 2, 3 and 4) When the annealing temperature is further increased to T (?) 970K, the clean surface of Si is restored, indicating that oxygen is completely desorbed.