PBTI Investigation of MoS2 n-MOSFET With Al2O3 Gate Dielectric

For the first time, we report the positive bias temperature instability of the back gated multilayer MoS
₂
n-MOSFETs with Al
₂
O
₃
gate dielectric. In the stress phase, the I
_d
-V
_g
curve shifts to the positive gate bias. In the recovery phase, it shifts back to the negative gate bias. After 5000 s recovery, it completely recovers to that of the fresh device. The results indicate that the voltage shift is solely due to trapping and detrapping of the pre-existing border traps in the Al
₂
O
₃
dielectric. The traps consist of fast and slow components with the capture time constants of 7 and 1.8 × 10
²
s and the emission time constants of 15 and 1.0 × 10
³
s, respectively. The results from first-order trapping and detrapping calculations are in overall agreements with 12 measured AV
_g
curves including six under stress voltages and six in the recovery phases. The energy densities for the fast and slow traps are derived to be in the order of 10
¹³
cm
^-2
eV
^-1
above the bottom of the MoS
₂
conduction band.