Addressing the Performance and Reliability Bottlenecks in 2D Transition Metal Dichalcogenide (TMD) Based Transistor Technology

Abstract

In this thesis, we presented different contributions towards the development of 2D material technology. Firstly the realization of desired dimensions over singlecrystal high-quality MoS2 material through dry etching techniques. SF6 plasma induces large residue over the material, inhibiting the application despite its advantage over SiO2 etch selectivity. On the other hand, CHF3 plasma is shown to give a well-controlled etching process with its relatively lower etch rate than SF6 plasma. However, under over-etch conditions, plasma is observed to introduce two significant challenges. The first is the doping induced by high-energy fluorine radicals diffused through resist and the TMD material. The second one is the crystal damage caused by plasma from the side walls elimination of these two challenges required highly controlled etching. Optimized and controlled etching using CHF3 plasma resulted in transistors’ fabrication without compromising the performance compared to reference transistors. The same controlled etching process is observed to apply to other TMDs as well. Transistors implemented with such an approach have shown no degradation in performance metrics than standard devices, thus generalizing the process applicability to all TMDs.