Improved electrical properties of MoS transistor with Hf1-xO as gate dielectric

Xinyuan Zhao, J. P. Xu, L. Liu, P. T. Lai, W. M. Tang

Research output: Chapter in book / Conference proceedingConference article published in proceeding or bookAcademic researchpeer-review

Abstract

Carrier mobility of MoS transistor can be greatly improved by screening the Columbic scattering by a high-k gate dielectric. In this work, different TiO amounts are incorporated into HfO to form Hf1-xO gate dielectrics to investigate its effects on the electrical properties of MoS transistor. It is found that enhanced carrier mobility and decreased gate leakage current can be achieved by optimizing the Ti content, i.e. with {\rm{Hf}}-{0.9}{\rm{Ti}}-{0.1}O (x\ =\ 0.1) as the gate dielectric, the device exhibits the highest carrier mobility of 31.5 {\rm{cm}}^{2}/Vs, which is 1.3\times improvement as compared to the sample with HfO as gate dielectric (24.1\ {\rm{cm}}^{2}/Vs). The main mechanism lies in that Hf1-xO has higher k value than HfO to increase the Coulomb screening effect and thus carrier mobility. However, with further increase of Ti content, e.g. {\rm{Hf}}-{0.85}{\rm{Ti}}-{0.15}O (x=\ 0.15), the device exhibits larger off current and degraded subthreshold swing. This is probably attributed to Ti-related oxide traps, a decreased conduction-band offset between {\rm{Hf}}-{0.85}{\rm{Ti}}-{0.15}{\rm{O}} and MoS, and degraded MoS-{2}/{\rm{Hf}}-{1-x}{\rm{Ti}}-{x}{\rm{O}} interface quality.

Original languageEnglish
Title of host publication2019 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2019
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781728102863
DOIs
Publication statusPublished - 1 Jun 2019
Event2019 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2019 - Xi'an, China
Duration: 12 Jun 201914 Jun 2019

Publication series

Name2019 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2019

Conference

Conference2019 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2019
CountryChina
CityXi'an
Period12/06/1914/06/19

Keywords

  • Carrier mobility
  • Conduction-band offset
  • Coulomb screening effect
  • Hf-TiO gate dielectric
  • MoS transistor

ASJC Scopus subject areas

  • Signal Processing
  • Electrical and Electronic Engineering
  • Instrumentation

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