ALD-ZrO<sub>2</sub> gate dielectric with suppressed interfacial oxidation for high performance MoS<sub>2</sub> top gate MOSFETs
Wen-Hsin Chang, Naoya Okada, Masayo Horikawa, Takahiko Endo, Yasumitsu Miyata, Toshifumi Irisawa
Abstract
Abstract To enhance the feasibility of 2-dimensional transition metal dichalcogenides (TMDCs) channels in future nano-electronic and optoelectronic devices, a top gate device structure fabricated with very-large-scale-integration compatible process is mandatory. High- κ dielectric ZrO 2 has been directly deposited on MoS 2 through low-temperature atomic layer deposition (ALD) without any surface protection layers. The uniform growth of ZrO 2 on MoS 2 was confirmed to be caused by the physical adsorption, resulting in the suppressed interfacial oxidation and the reduced damage of monolayer (1L) MoS 2 channel. Low thermal budget post-deposition annealing was found to be effective for reducing interfacial traps between ZrO 2 and MoS 2 interface, thus enhancing the device performances of 1L MoS 2 nMOSFETs. Low capacitance equivalent thickness (CET) of ZrO 2 of 2.3 nm has been achieved while maintaining decent device performance, indicating low-temperature ALD is promising for future TMDC top gate devices with a high-quality interface and thin CET.