Enhancement-mode accumulation capacitance-voltage characteristics in TiN/ALD-Al2O3/sputtered-MoS2 top-gated stacks

Abstract

This study demonstrates atomic layer deposition of an Al2O3 film on a sputtered-MoS2 film and capacitance-voltage (C-V) characteristics of TiN top-gated metal-insulator-semiconductor field-effect-transistors with a sputtered-MoS2 channel. A uniform Al2O3 film was formed directly on a sputtered-MoS2 film with no pretreatment. From chemical analysis and surface observation, it is speculated that dangling bonds on a sputtered-MoS2 surface work as nucleation sites of Al2O3. The fabricated top-gated stacks show enhancement-mode accumulation C-V characteristics owing to the low carrier density of the MoS2 film resulting from sputtering and sulfur-powder annealing. This study is the first step for systematic investigation and discussion on not only C-V characteristics but also carrier transport of MoS2 films.