1 research outputs found
Improving the Stability of High-Performance Multilayer MoS<sub>2</sub> Field-Effect Transistors
In
this study, we propose a method for improving the
stability of multilayer MoS<sub>2</sub> field-effect transistors (FETs)
by O<sub>2</sub> plasma treatment and Al<sub>2</sub>O<sub>3</sub> passivation
while sustaining the high performance of bulk MoS<sub>2</sub> FET.
The MoS<sub>2</sub> FETs were exposed to O<sub>2</sub> plasma for
30 s before Al<sub>2</sub>O<sub>3</sub> encapsulation to achieve a
relatively small hysteresis and high electrical performance. A MoO<i><sub>x</sub></i> layer formed during the plasma treatment was
found between MoS<sub>2</sub> and the top passivation layer. The MoO<i><sub>x</sub></i> interlayer prevents the generation of excess
electron carriers in the channel, owing to Al<sub>2</sub>O<sub>3</sub> passivation, thereby minimizing the shift in the threshold voltage
(<i>V</i><sub>th</sub>) and increase of the off-current
leakage. However, prolonged exposure of the MoS<sub>2</sub> surface
to O<sub>2</sub> plasma (90 and 120 s) was found to introduce excess
oxygen into the MoO<i><sub>x</sub></i> interlayer, leading
to more pronounced hysteresis and a high off-current. The stable MoS<sub>2</sub> FETs were also subjected to gate-bias stress tests under
different conditions. The MoS<sub>2</sub> transistors exhibited negligible
decline in performance under positive bias stress, positive bias illumination
stress, and negative bias stress, but large negative shifts in <i>V</i><sub>th</sub> were observed under negative bias illumination
stress, which is attributed to the presence of sulfur vacancies. This
simple approach can be applied to other transition metal dichalcogenide
materials to understand their FET properties and reliability, and
the resulting high-performance hysteresis-free MoS<sub>2</sub> transistors
are expected to open up new opportunities for the development of sophisticated
electronic applications