Ultrathin calcium fluoride insulators for two-dimensional field-effect transistors
Two-dimensional semiconductors could be used to fabricate ultimately scaled field-effect transistors and more-than-Moore nanoelectronic devices. However, these targets cannot be reached without appropriate gate insulators that are scalable to the nanometre range. Typically used oxides such as SiO 2...
Gespeichert in:
Veröffentlicht in: | Nature electronics 2019-06, Vol.2 (6), p.230-235 |
---|---|
Hauptverfasser: | , , , , , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Two-dimensional semiconductors could be used to fabricate ultimately scaled field-effect transistors and more-than-Moore nanoelectronic devices. However, these targets cannot be reached without appropriate gate insulators that are scalable to the nanometre range. Typically used oxides such as SiO
2
, Al
2
O
3
and HfO
2
are, however, amorphous when scaled, and 2D hexagonal boron nitride exhibits excessive gate leakage currents. Here, we show that epitaxial calcium fluoride (CaF
2
), which can form a quasi van der Waals interface with 2D semiconductors, can serve as an ultrathin gate insulator for 2D devices. We fabricate scalable bilayer MoS
2
field-effect transistors with a crystalline CaF
2
insulator of ~2 nm thickness, which corresponds to an equivalent oxide thickness of less than 1 nm. Our devices exhibit low leakage currents and competitive device performance characteristics, including subthreshold swings down to 90 mV dec
−1
, on/off current ratios up to 10
7
and a small hysteresis.
High-performance MoS
2
transistors can be created using 2-nm-thick CaF
2
as a gate insulator, which forms a quasi van der Waals interface with the 2D semiconductor. |
---|---|
ISSN: | 2520-1131 2520-1131 |
DOI: | 10.1038/s41928-019-0256-8 |