Improved Leakage and Reliability for ${rm ZrLaO}_{x}/{rm ZrTiO}_{x}/{rm ZrLaO}_{x}$-Based MIM Capacitors by Plasma Nitridation

摘要

In this letter, ${rm ZrLaO}_{rm x}/{rm ZrTiO}_{rm x}/{rm ZrLaO}_{rm x}$ laminate is employed as the platform for investigating the effects of plasma nitridation on the electrical performance and reliability of metal–insulator–metal capacitors. After plasma nitridation of ${rm ZrTiO}_{rm x}$, the capacitance density and quadratic voltage coefficient of capacitance (VCC-$alpha$) degraded slightly to 14.38 ${rm fF}/mu{rm m}^{rm 2}$ and 68 ${rm ppm/V}^{rm 2}$. These results meet the International Technology Roadmap for Semiconductors requirements for implementation in 2020. The major benefits of plasma nitridation are the enhanced performance of the electrical characteristics and reliability. The process reduces leakage current by a factor of 32.8, and improves stress-induced leakage current by a factor of 10.6. In addition, near frequency-independent capacitance is achieved after stressing at 2.5 V for 1000 s, and a desirable reliability of 0.27% capacitance change after a 10-year operation under 2.5-V stress is attained. These results suggest that nitrided ${rm ZrTiO}_{rm x}$ enables ${rm ZrLaO}_{rm x}/{rm ZrTiO}_{rm x}/{rm ZrLaO}_{rm x}$ laminate to be a candidate for use in advanced circuit applications.