Speaker
Prof.
Thomas Osipowicz
(National University of Singapore, Singapore)
Description
Recently, interest in the semiconductor research community has switched, to some degree, from Si based devices to materials with higher carrier mobilities, such as germanium, germanium-tin, and compound semiconductors. This is also driven by the need to extend the functionalities of silicon IC technology to enable optical interconnect systems, i.e. find a direct bandgap material that can be integrated with Si process technology. Germanium-tin (GeSn) alloys promise to deliver on both these aspects; they may become technologically important materials.
Here we report on Channeling Contrast Microscopy GeSn thin films grown by Molecular Beam Epitaxy (MBE) at temperatures of 170-150°C. This technique allows epitaxial growth of thin films with sub monolayer precision. The films were grown with Sn concentrations up to 16% and display excellent crystal quality.
Broad beam conventional and high resolution RBS was used to determine the depth profiles, and angular scans around the (100) axis were carried out to assess crystal and interface quality. Channeling Contrast Microscopy (CCM) at sub-micron resolutions in an optimized detector geometry was used to acquire depth resolved images of lateral in homogeneities, surface morphologies and lattice tilts, in order to optimize the growth methodology.
Primary author
Prof.
Thomas Osipowicz
(National University of Singapore, Singapore)
Co-authors
Prof.
Eng Soon Tok
(Department of Physics, National University of Singapore, Singapore)
Dr
Taw Kuei Chan
(Centre for Ion Beam Applications, Physics Department, National University of Singapore, Singapore)
Dr
Wei Wang
(Department of Electrical and Computer Engineering, National University of Singapore, Singapore)
Prof.
Yee-Chia Yeo
(Department of Electrical and Computer Engineering, National University of Singapore, Singapore)
