Bias Temperature Stress Instability of Multilayered MoS2 Field-Effect Transistors With CYTOP Passivation

Bias temperature stress instability on multi-layered MoS2 FETs was systematically investigated with the device scheme encapsulated with amorphous fluoropolymers [cyclized transparent optical polymer (CYTOP)] for the secure of minimization of external gas ambient effects. Large threshold voltage shifts (Delta V-th) for the negative bias temperature stress (NBTS) were observed, compared to the positive bias temperature stress (PBTS). Herein, the asymmetry behaviors on Delta V-th, observed in this paper, are ascribed to the sulfur vacancy in MoS2 layers, leading to large hole traps compared to electron traps in MoS2 layers. Moreover, high-temperature-sensitivity [d (Delta V-th)/dT] on Delta V-th for PBTS than NBTS was observed, and their origins are possibly due to synergetic effects associated with large trap energy distribution (k(o)T) for electron trap levels.