Abstract
ALD Al 2 O 3 films treated respectively by N 2 , O 2 and NH 3 plasmas are used as gate dielectrics to fabricate few-layered MoS 2 FETs. As compared with the control sample without any plasma treatment, the devices with different plasmas treatments achieve better electrical properties, with the NH 3 -treated device having the best results: highest carrier mobility of 39.3 cm 2 /Vs (~1.65 times higher than that of the control sample), smallest subthreshold swing of 90.9 mV/dec, largest on/off ratio of 1.5 × 10 7 and negligible hysteresis. These are attributed to the fact that the NH 3 plasma treatment can (1) effectively passivate the oxygen vacancies in Al 2 O 3 and decrease the dangling bonds at the Al 2 O 3 surface, thus reducing the traps at/near the Al 2 O 3 /MoS 2 interface; (2) increase the k value of the dielectric by N incorporation to enhance the screening effect on the Coulomb impurity scattering. In addition, these plasma treatments can adjust the MoS 2 FET from depletion mode to enhancement mode by introducing negative ions into the gate dielectric.
Original language | English |
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Pages (from-to) | 1028-1034 |
Number of pages | 7 |
Journal | Applied Surface Science |
Volume | 481 |
DOIs | |
Publication status | Published - 1 Jul 2019 |
Keywords
- Al O dielectric
- Mobility
- MoS FETs
- Plasma treatment
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- General Physics and Astronomy
- Surfaces and Interfaces
- Surfaces, Coatings and Films