TY - GEN
T1 - Improved electrical properties of MoS transistor with Hf1-xO as gate dielectric
AU - Zhao, Xinyuan
AU - Xu, J. P.
AU - Liu, L.
AU - Lai, P. T.
AU - Tang, W. M.
PY - 2019/6/1
Y1 - 2019/6/1
N2 - 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.
AB - 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.
KW - Carrier mobility
KW - Conduction-band offset
KW - Coulomb screening effect
KW - Hf-TiO gate dielectric
KW - MoS transistor
UR - http://www.scopus.com/inward/record.url?scp=85069505723&partnerID=8YFLogxK
U2 - 10.1109/EDSSC.2019.8754077
DO - 10.1109/EDSSC.2019.8754077
M3 - Conference article published in proceeding or book
T3 - 2019 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2019
BT - 2019 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2019
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2019 IEEE International Conference on Electron Devices and Solid-State Circuits, EDSSC 2019
Y2 - 12 June 2019 through 14 June 2019
ER -