Impact of In Situ Oxidation-Resulted High-k Passivation Layer on Device Stability and Mobility Improvement

The performance of nanoelectronic devices can be significantly improved using high-k dielectric materials. However, the interface between the gate dielectric and channel can impact the device's stability and performance. To address this issue, a new approach is developed that involves incorporating high-k dielectric into the channel via in situ oxidation of air-sensitive 2D materials. Herein, the impact of HfSe2 thermal oxidation on the electrical properties of the MoS2 channel is investigated. The findings demonstrate that incomplete oxidation of HfSe2 on the MoS2 channel introduces significant border traps, leading to device performance degradation. In contrast, complete oxidation of HfSe2 leads to the formation of high-k HfOx. The MoS2 field-effect transistors capped by in situ thermally oxidized HfOx show a twofold enhancement in field-effect mobility and improved gate bias stress stability. These findings suggest that the integration of high-k dielectrics via in situ oxidation has great potential for high-performance electronic device applications.