Ge N-Channel MOSFETs with ZrO2 Dielectric Achieving Improved Mobility

Abstract

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

• Germanium
• ZrO2
• MOSFET
• CMOS
• Mobility