Polymer/oxide bilayer dielectric for hysteresis-minimized 1 v operating 2D TMD transistors

Abstract

Despite their huge impact on future electronics, two-dimensional (2D) dichalcogenide semiconductor (TMD) based transistors suffer from the hysteretic characteristics induced by the defect traps located at the dielectric/TMD channel interface. Here, we introduce a hydroxyl-group free organic dielectric divinyl-Tetramethyldisiloxane-bis (benzocyclobutene) (BCB) between the channel and conventional SiO2 dielectric, to practically resolve such issues. Our results demonstrate that the electrical hysteresis in the n-channel MoS2 and p-channel MoTe2 transistors were significantly reduced to less than ∼20% of initial value after being treated with hydrophobic BCB dielectric while their mobilities increased by factor of two. Such improvements are certainly attributed to the use of the hydroxyl-group free organic dielectric, since high density interface traps are related to hydroxyl-groups located on hydrophilic SiO2. This concept of interface trap reduction is extended to stable low voltage operation in 2D MoTe2 FET with 30 nm BCB/10 nm Al2O3 bilayer dielectric, which operates well at 1 V. We conclude that the interface engineering employing the BCB dielectric offers practical benefits for the high performance and stable operation of TMD-based transistors brightening the future of 2D TMD electronics.