Electron Mobility Degradation Due to Remote Coulomb Scattering in Ge MOSFET

DOI

10.2991/cset-16.2016.72How to use a DOI?

Keywords

Ge, mobility, remote coulomb scatterings

Abstract

Remote Coulomb scatterings (RCS) on electron mobility degradation are experimentally investigated in Ge based metal-oxide-semiconductor field-effect-transistor (MOSFETs) with GeOx/Al2O3 gate stacks. The mobility is found increased with thicker GeOx (7.8-20.8 ). The physical origin of this mobility dependence on GeOx thickness is explored. The following factors are excluded: Coulomb scattering due to interfacial traps at GeOx/Ge, phonon scattering, and surface roughness scattering. Therefore, the RCS from charges in gate stacks are studied. The charge distributions in GeOx/Al2O3 gate stacks are experimentally evaluated. The bulk charges in Al2O3 and GeOx are found negligible. The density of interfacial charge is +3.2ž1012 cm-2 at GeOx/Ge interface, and -2.3ž1012 cm-2 at Al2O3/GeOx interface. The electric dipole at Al2O3/GeOx interface is found +0.15 V, corresponding to areal charge density of 1.9ž1013 cm-2. The origin of this mobility dependence on GeOx thickness is attributed to the RCS due to electric dipole at Al2O3/GeOx interface. And this remote dipole scattering is found to play a significant role on mobility degradation. The discovery of this new scattering mechanism indicates that engineering of Al2O3/GeOx interface is key for mobility enhancement and device performance improvement. These results are helpful for understanding and engineering the Ge mobility enhancement.

Copyright

© 2016, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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TY  - CONF
AU  - Haoyu Xu
AU  - Jing Zhang
AU  - Shuhua Wei
AU  - Xiaolei Wang
AU  - Wenwu Wang
PY  - 2016/08
DA  - 2016/08
TI  - Electron Mobility Degradation Due to Remote Coulomb Scattering in Ge MOSFET
BT  - Proceedings of the 2016 International Conference on Computer Science and Electronic Technology
PB  - Atlantis Press
SP  - 310
EP  - 313
SN  - 2352-538X
UR  - https://doi.org/10.2991/cset-16.2016.72
DO  - 10.2991/cset-16.2016.72
ID  - Xu2016/08
ER  -