Ge N-Channel MOSFETs with ZrO(2) Dielectric Achieving Improved Mobility

High-mobility Ge nMOSFETs with ZrO(2) gate dielectric are demonstrated and compared against transistors with different interfacial properties of ozone (O(3)) treatment, O(3) post-treatment and without O(3) treatment. It is found that with O(3) treatment, the Ge nMOSFETs with ZrO(2) dielectric having a EOT of 0.83 nm obtain a peak effective electron mobility (μ(eff)) of 682 cm(2)/Vs, which is higher than that of the Si universal mobility at the medium inversion charge density (Q(inv)). On the other hand, the O(3) post-treatment with Al(2)O(3) 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 × 10(12) cm(−2). These results indicate the potential utilization of ZrO(2) dielectric in high-performance Ge nMOSFETs.