AVS 51st International Symposium
    Surface Science Wednesday Sessions
       Session SS2-WeM

Paper SS2-WeM2
Identification of Si and Ge on the Hydrogen-Terminated Ge/Si(001) Surfaces for Observation of Intermixing

Wednesday, November 17, 2004, 8:40 am, Room 210C

Session: Semiconductor Surface and Interface Structure
Presenter: Y. Fujikawa, Tohoku University, Japan
Authors: Y. Fujikawa, Tohoku University, Japan
A. Kuwano, Tohoku University, Japan
M. Kawashima, Tohoku University, Japan
Y. Yamada-Takamura, Tohoku University, Japan
T. Nagao, Tohoku University, Japan
T. Sakurai, Tohoku University, Japan
Correspondent: Click to Email
Control of the local composition of SiGe films in an atomic level is of great technological importance for designing the SiGe nanodevices. Intermixing effect between Si and Ge is the key issue to achieve precise composition control at the surface layer. It has been known that hydrogen-rich condition at ~300 degree C induces segregation of Si to the surface layer on the Ge covered Si(001) surface, while Ge prefers to stay at the surface layer without hydrogen@footnote 1@. This result implies that the hydrogen-annealing treatment is a useful method to control the composition of SiGe surface layer. We investigated the hydrogen-terminated Ge/Si(001) surface using STM to find that Ge-H sites are imaged as brighter protrusions in comparison with Si-H sites under the empty-state imaging condition. This effect is similar to the case of Cl-terminated Ge/Si(001) surface, which was observed recently@footnote 2@. Si-H and Ge-H sites on the hydrogen-terminated Ge/Si(001) with a Ge coverage of 1.5 ML were resolved successfully using this empty-state imaging condition to study the atomic process of intermixing. Furthermore, it turned out that the Si segregation by the hydrogen-annealing produces significantly bright features beside the dimer-row vacancies (DVLs), in addition to the features coming from Ge-H and Si-H sites. This feature can be attributed to the broken rebonded structure inside the DVL, which contributes the re-adjustment of the surface strain which is modified by the Si segregation. @FootnoteText@ @footnote 1@ Rudkevich et al., Phys. Rev. Lett. 81, 3467 (1998).@footnote 2@ Lin et al., Phys. Rev. Lett. 90, 046102 (2003).