Ge N-Channel MOSFETs with ZrO2 Dielectric Achieving Improved Mobility

Lulu Chou; Yan Liu; Yang Xu; Yue Peng; Huan Liu; Xiao Yu; Genquan Han; Yue Hao

doi:10.1186/s11671-021-03577-0

Ge N-Channel MOSFETs with ZrO₂ Dielectric Achieving Improved Mobility

Nanoscale Res Lett. 2021 Aug 4;16(1):125. doi: 10.1186/s11671-021-03577-0.

Authors

Lulu Chou¹, Yan Liu¹, Yang Xu¹, Yue Peng¹, Huan Liu^{1

2}, Xiao Yu³, Genquan Han⁴, Yue Hao¹

Affiliations

¹ State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an, 710071, People's Republic of China.
² Intelligent Chip Research Center, Zhejiang Lab, Hangzhou, 311121, People's Republic of China.
³ Intelligent Chip Research Center, Zhejiang Lab, Hangzhou, 311121, People's Republic of China. yuxiao@zhejianglab.com.
⁴ State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an, 710071, People's Republic of China. gqhan@xidian.edu.cn.

Abstract

High-mobility Ge nMOSFETs with ZrO₂ gate dielectric are demonstrated and compared against transistors with different interfacial properties of ozone (O₃) treatment, O₃ post-treatment and without O₃ treatment. It is found that with O₃ treatment, the Ge nMOSFETs with ZrO₂ dielectric having a EOT of 0.83 nm obtain a peak effective electron mobility (μ_eff) of 682 cm²/Vs, which is higher than that of the Si universal mobility at the medium inversion charge density (Q_inv). On the other hand, the O₃ post-treatment with Al₂O₃ interfacial layer can provide dramatically enhanced-μ_eff, achieving about 50% μ_eff improvement as compared to the Si universal mobility at medium Q_inv of 5 × 10¹² cm^-2. These results indicate the potential utilization of ZrO₂ dielectric in high-performance Ge nMOSFETs.

Keywords: CMOS; Germanium; MOSFET; Mobility; ZrO2.