Title: Threshold voltage shifts in Si passivated (100)Ge p-channel field effect transistors: Insights from first-principles modeling
Authors: Pourtois, G ×
Houssa, Michel
De Jaeger, B
Kaczer, B
Leys, F
Meuris, M
Caymax, M
Groeseneken, Guido
Heyns, Marc #
Issue Date: Jul-2007
Publisher: Amer inst physics
Series Title: Applied Physics Letters vol:91 issue:2 pages:023506-1-023506-3
Article number: 023506
Abstract: An asymmetric shift of the capacitance-voltage characteristics of n-Ge/Si/SiOx/HfO2/TaN p-channel field effect transistor is reported, namely, a shift of the threshold voltage toward positive values in inversion, while the flatband voltage remains constant. First-principles calculations on silicon-passivated germanium surfaces reveal the formation of a dipole layer at the germanium/silicon interface, which leads to a decrease of the substrate work function/threshold voltage by 0.4-0.5 V. Silicon-induced surface states are also found in the germanium band gap. When the substrate Fermi level is located near these states, electrons are transferred to the silicon layer and compensate the work function shift, explaining the absence of flatband voltage shift. (C) 2007 American Institute of Physics.
ISSN: 0003-6951
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Electrical Engineering - miscellaneous
Semiconductor Physics Section
ESAT - MICAS, Microelectronics and Sensors
Surface and Interface Engineered Materials
× corresponding author
# (joint) last author

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