Ba termination of Ge(001) studied with STM.
Ba termination of Ge(001) studied with STM.
复制标题
使用 STM 研究 Ge(001) 的 Ba 终止。
DOI：
10.1088/0957-4484/26/15/155701
复制
发表时间：
2015
期刊：
影响因子：
3.5
通讯作者：
Koczorowski W
中科院分区：
文献类型：
--
作者：
Koczorowski W
我们使用受控退火来调整沉积在Ge（001）上的Ba原子的亚单层和单层覆盖的界面性质，从而能够产生两种基本不同的界面相之一，正如扫描隧道显微镜所揭示的那样。首先，我们确定了两个关键的结构相与此吸附系统，即在顶部吸附和表面合金的形成，通过进行沉积和退火实验，在覆盖率足够低（0.15 ML），孤立的Ba相关的功能可以单独解决。随后，我们调查的单层覆盖的情况下，感兴趣的钝化计划的未来的Ge基器件，我们发现，Ba的热蒸发到Ge（001）表面在室温下的结果在顶部吸附。Ba和Ge层之间的这种分离（缺乏混合）通过连续退火步骤保持到470、570、670和770 K的温度，尽管在570 K及以上观察到Ba层的逐渐有序，伴随着Ba层密度的降低。高于770 K的退火产生2D表面合金相，伴随着通过单层高度沟槽形成的应变消除。1070 K的退火温度看到表面形态的进一步变化，但保留2D表面合金特性。这些结果进行了讨论，鉴于其可能的影响，为未来的半导体集成电路技术。
We use controlled annealing to tune the interfacial properties of a sub-monolayer and monolayer coverages of Ba atoms deposited on Ge (001), enabling the generation of either of two fundamentally distinct interfacial phases, as revealed by scanning tunneling microscopy. Firstly we identify the two key structural phases associated with this adsorption system, namely on-top adsorption and surface alloy formation, by performing a deposition and annealing experiment at a coverage low enough (∼ 0.15 ML) that isolated Ba-related features can be individually resolved. Subsequently we investigate the monolayer coverage case, of interest for passivation schemes of future Ge based devices, for which we find that the thermal evaporation of Ba onto a Ge (001) surface at room temperature results in on-top adsorption. This separation (lack of intermixing) between Ba and Ge layers is retained through successive annealing steps to temperatures of 470, 570, 670 and 770 K although a gradual ordering of the Ba layer is observed at 570 K and above, accompanied by a decrease in Ba layer density. Annealing above 770 K produces the 2D surface alloy phase accompanied by strain relief through monolayer height trench formation. An annealing temperature of 1070 K sees a further change in surface morphology but retention of the 2D surface alloy characteristic. These results are discussed in view of their possible implications for future semiconductor integrated circuit technology.