Paul Neelima, Filimonov Sergey, Cherepanov Vasily, Cakmak Mehmet, Voigtländer Bert
Institute of Bio- and Nanosystems (IBN 3), and cni - Center of Nanoelectronic Systems for Information Technology, Research Center Jülich, 52425 Jülich, Germany.
Phys Rev Lett. 2007 Apr 20;98(16):166104. doi: 10.1103/PhysRevLett.98.166104.
The chemical contrast between Si and Ge obtained by scanning tunneling microscopy on Bi-covered Si(111) surfaces is used as a tool to identify two vertical Ge/Si intermixing processes. During annealing of an initially pure Ge monolayer on Si, the intermixing is confined to the first two layers approaching a 50% Ge concentration in each layer. During epitaxial growth, a growth front induced intermixing process acting at step edges is observed. Because of the open atomic structure at the step edges, relative to the terraces, a lower activation barrier for intermixing at the step edge, compared to the terrace, is observed.
通过扫描隧道显微镜在铋覆盖的硅（111）表面获得的硅和锗之间的化学对比度，被用作识别两种垂直锗/硅混合过程的工具。在硅上最初的纯锗单层退火过程中，混合局限于前两层，每层接近50%的锗浓度。在外延生长过程中，观察到在台阶边缘起作用的生长前沿诱导混合过程。由于台阶边缘相对于台面具有开放的原子结构，与台面相比，观察到台阶边缘混合的活化能垒更低。
