Photoetching of Si(111)-(7x7) studied by STM
Photoetching of Si(111)-(7x7) studied by STM
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DOI：
10.1016/s0039-6028(96)01403-3
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发表时间：
1997-04-10
期刊：
影响因子：
1.9
通讯作者：
Rogers, D
中科院分区：
文献类型：
--
作者：
Chen, XH;Polanyi, JC;Rogers, D
用193 nm准分子激光辐照部分氯化的Si(111)-(7x7)表面。使用扫描隧道显微镜(STM)计算每单位光照时间的光刻原子数。从室温到1055℃的峰值表面温度范围内，吸附原子的刻蚀速率随着注量的增加而线性增加。这个曲线图的斜率意味着每个光子3.4×10(-8)个原子的恒定刻蚀速率，即sigma(E)=1.8×10(-22)cm(2)。在这个宽广的温度范围内，表面温度对刻蚀速率没有影响。因此，硅吸附原子的去除直接是由于光解作用，推测是光解形成的电子-空穴对。分别测定了单原子、双原子和三原子空位的刻蚀速率对强度的依赖关系，得出了相应的光过程分别涉及一个、两个和三个光子的结论。对抛射的原子对分布函数的统计分析给出了直接靠近单原子空位的光刻几率增加大于或接近>；10(2)的证据。未氯化表面的辐照也导致吸附原子刻蚀，其刻蚀速率随剂量线性增加，但与光刻相对应的刻蚀速率较低，其截面为sigma(E)=0.52×10(-22)cm(2)。(C)1997年爱思唯尔科学公司。
A partially chlorinated Si(111)-(7x7) surface was subjected to 193 nm excimer laser radiation. Scanning tunnelling microscopy (STM) was used to count the number of photoetched atoms per unit of illumination time. The adatom etch rate increased linearly with fluence for peak surface temperatures ranging from room temperature up to 1055 degrees C. The slope of this plot implied a constant etch rate of 3.4x10(-8) atoms per photon, i.e. sigma(e) = 1.8x10(-22) cm(2). The surface temperature did not influence the etch rate over this broad temperature range. It follows that the removal of Si adatom was directly due to photolysis, the presumed agents being photoformed electron-hole pairs. The intensity dependence of the etch rate was determined separately for one-, two- and three-atom vacancies, leading to the conclusion that the corresponding photoprocesses involved one, two and three photons, respectively. A statistical analysis of the pair-distribution function for ejected adatoms gave evidence of an increase of greater than or similar to>10(2) in photoetching probability directly adjacent to a single-atom vacancy. Irradiation of the unchlorinated surface also resulted in adatom etching which increased linearly with fluence, but at a lower etch rate corresponding to photoetching with a cross-section of sigma(e) = 0.52x10(-22) cm(2). (C) 1997 Elsevier Science B.V.