Monolayer-MoS₂ Stacked Nanosheet Channel with C-type Metal Contact

This work demonstrates the first stacked nanosheet devices with monolayer MoS₂ channel after successful simultaneous release of 2 nanosheets. Two-stacked monolayer MoS₂ nanosheets with 50-nm width can be released free up to 150 nm, proving excellent mechanical properties of the channel material. Conformal gate stack deposition on the 2-stacked MoS₂ sheets is confirmed. To increase contact area, we introduce here 'C-type' wrap-around contact that contacts not only the edge but also the top and bottom side on the monolayer MoS₂ channels. For the first time, studies of gate stack and its impact on subthreshold swing, threshold voltage and hysteresis are presented on single nanosheet gate all around (GAA) devices. Unlike most reports in literature of depletion-mode monolayer MoS₂ devices, through appropriate process control and interface engineering we report here positive threshold voltage for NMOS devices.