Oxide Formation on Si(100)-2×1 Surfaces Studied by Scanning Tunneling Microscopy/Scanning Tunneling Spectroscopy
Oxide Formation on Si(100)-2×1 Surfaces Studied by Scanning Tunneling Microscopy/Scanning Tunneling Spectroscopy
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通过扫描隧道显微镜/扫描隧道光谱研究 Si(100)-2×1 表面氧化物的形成
DOI：
10.1143/jjap.35.1593
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发表时间：
1996
影响因子：
1.5
通讯作者：
Yukio Yasuda Yukio Yasuda
中科院分区：
文献类型：
--
作者：
H. Ikegami;K. Ohmori;H. Ikeda;H. Iwano;Shigeaki Zaima Shigeaki Zaima;Yukio Yasuda Yukio Yasuda
用扫描隧道显微镜（STM）和扫描隧道谱（STS）研究了室温下Si（100）-2 1表面氧化物的形成过程。基于空间分辨STS谱，讨论了氧化引起的电子结构的变化。研究发现，在氧化的初始阶段，背键态和悬空键位的局域态密度（LDOS）在氧化诱导的亮突起处显著降低。暴露于4.5 L氧的2×1区域的STS光谱表明氧原子吸附在背键位点上。当SiO2平均厚度为0.4 nm时，Si（100）-2 1表面态完全消失，费米能级附近的差距宽度与体硅的禁带宽度非常接近。此外，所观察到的LDOS是空间均匀的，尽管在STM图像中的凸起的存在。STS光谱表明，形成的价带和导带的SiO2的氧化物厚度为0.4 nm。
The oxide formation on Si(100)-2×1 surfaces at room temperature has been studied by scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). The change in electronic structures due to oxidation has been discussed based on the spatially resolved STS spectra. It was found in the initial stage of oxidation that the local density-of-states (LDOS) of back bond states and dangling bond sites decreases dramatically at the oxidation-induced bright protrusions. The STS spectra of the 2×1 region with an oxygen exposure of 4.5 L suggest that oxygen atoms adsorb on the back bond sites. At the average SiO2 thickness of 0.4 nm, the surface states of Si(100)-2×1 vanish completely and the energy width of the gap near the Fermi level becomes very close to the band gap of bulk Si. In addition, the observed LDOS is spatially uniform in spite of the presence of bumps in the STM image. The STS spectra indicate the formation of the valence band and the conduction band of SiO2 at the oxide thickness of 0.4 nm.