Electricalperformance of multilayer MoS2 transistor with ALD HfTiO gate dielectric

2016 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2016, Hong Kong, 3-5 August 2016Electrical performance of MOS2 transistor, especially carrier mobility, can be greatly improved by screening the Columbic scattering by a high-k gate dielectric. In this work, Ti is incorporated into HfO2 to form HfTiO dielectric with a higher permittivity, which leads to further enhancement of the screening effect and thus carrier mobility. The effects of annealing ambient (N2, O2 and NH3) on the electrical performance of ALD HfTiO back-gated multilayer M0S2 transistor are investigated, and a highest mobility of 31.1 cm2/(V-s) is achieved for the NH3-annealed sample. However, different from the HfO2 gated MOS2 transistor, the HfTiO gated device exhibits larger off current and subthreshold swing. This is probably attributed to a smaller conduction-band offset between HfTiO and MOS2.Department of Applied Physic