1. FETs on 2-D Materials: Deconvolution of the Channel and Contact Characteristics by Four-Terminal Resistance Measurements on WSe2 Transistors.
- Author
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Sutar, Surajit, Asselberghs, Inge, Lin, Dennis H. C., Thean, Aaron Voon-Yew, and Radu, Iuliana
- Subjects
FIELD-effect transistors ,DECONVOLUTION (Mathematics) ,SEMICONDUCTORS ,SCHOTTKY barrier diodes ,LOGIC circuits - Abstract
FETs made on 2-D semiconductors, typically without degenerate doping at the contacts, have a significant Schottky junction (SJ) resistance, which complicates transistor analysis. This paper evaluates the effect of the contact resistance on the 2-D-material FET characteristics through four-terminal (4-T) resistance measurements on WSe2 FETs, which allow studying the channel and contacts characteristics separately. Apart from showing the nonnegligibility of contact resistance, this paper enables a finer understanding of commonly observed phenomena, such as transistor performance improvement with dielectric-encapsulation is observed to have a stronger effect on the contact than the channel; the resistance of the forward-biased SJ is observed to be not negligible, but comparable to that of the reverse-biased junction; at biases commonly referred to as “low-bias,” the WSe2 FET resistance could be dominated by the contacts; and pinchoff can be observed at relatively lower current levels, being related to the channel-contact resistance ratio rather than their magnitudes. In the devices where true channel pinchoff can be verified, a correlation emerges between current saturating behavior and asymmetry in the output characteristics with respect to the drain–source bias polarity, a feature that may serve as a guide toward interpreting standard FET output characteristics in 2-D materials. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
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