The role of phase separation for self-organized surface pattern formation by ion beam erosion and metal atom co-deposition
The role of phase separation for self-organized surface pattern formation by ion beam erosion and metal atom co-deposition
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DOI：
10.1007/s00339-012-7285-8
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发表时间：
2013-05-01
影响因子：
2.7
通讯作者：
Broetzmann, M.
中科院分区：
文献类型：
--
作者：
Hofsaess, H.;Zhang, K.;Broetzmann, M.
我们研究了在室温下，在不同的金属共沉积表面活性剂原子的同时沉积下，在正入射离子束侵蚀Si表面上的涟漪图案的形成。已知少量金属原子（特别是Fe和Mo）的共沉积对Si上纳米级表面图案的演变具有巨大影响。在以前的工作中，在共沉积的Fe原子的Si的离子侵蚀，我们提出，在离子束侵蚀过程中形成的稳态混合FexSi表面层的Fe和Si原子之间的化学相互作用是一个主导的驱动力自组织图案的形成。特别是，我们提供了实验证据的形成非晶二硅化铁。为了确认和概括这种化学效应的图案形成，特别是相分离的趋势，我们现在已经照射Si表面与正常入射5 keV的负离子的同时gracing入射共沉积的Fe，Ni，Cu，Mo，W，Pt，和Au表面活性剂原子。两组中的所选金属（Fe、Ni、Cu）和（W、Pt、Au）在它们的碰撞级联行为方面非常相似，但在它们的硅化物形成倾向方面有很大不同。我们发现明显的涟漪图案的形成只为那些共沉积的金属（铁，钼，镍，钨，铂），这是容易形成的单和二硅化物。相比之下，对于Cu和Au共沉积，即使在高离子注量下照射后，表面仍保持非常平坦。由于Cu与Fe、Ni相比以及Au与W、Pt相比具有非常不同的行为，因此在Fe、Mo、Ni、W和Pt共沉积的情况下，朝向非晶金属硅化物相的相分离被视为在Si上形成图案的相关过程。
We investigate the ripple pattern formation on Si surfaces at room temperature during normal incidence ion beam erosion under simultaneous deposition of different metallic co-deposited surfactant atoms. The co-deposition of small amounts of metallic atoms, in particular Fe and Mo, is known to have a tremendous impact on the evolution of nanoscale surface patterns on Si. In previous work on ion erosion of Si during co-deposition of Fe atoms, we proposed that chemical interactions between Fe and Si atoms of the steady-state mixed FexSi surface layer formed during ion beam erosion is a dominant driving force for self-organized pattern formation. In particular, we provided experimental evidence for the formation of amorphous iron disilicide. To confirm and generalize such chemical effects on the pattern formation, in particular the tendency for phase separation, we have now irradiated Si surfaces with normal incidence 5 keV Xe ions under simultaneous gracing incidence co-deposition of Fe, Ni, Cu, Mo, W, Pt, and Au surfactant atoms. The selected metals in the two groups (Fe, Ni, Cu) and (W, Pt, Au) are very similar regarding their collision cascade behavior, but strongly differ regarding their tendency to silicide formation. We find pronounced ripple pattern formation only for those co deposited metals (Fe, Mo, Ni, W, and Pt), which are prone to the formation of mono and disilicides. In contrast, for Cu and Au co-deposition the surface remains very flat, even after irradiation at high ion fluence. Because of the very different behavior of Cu compared to Fe, Ni and Au compared to W, Pt, phase separation toward amorphous metal silicide phases is seen as the relevant pro-cess for the pattern formation on Si in the case of Fe, Mo, Ni, W, and Pt co-deposition.