Electrical and Reliability Characteristics of FinFETs With High-k Gate Stack and Plasma Treatments

Effects of high- ${k}$ gate stacks and plasma treatments on electrical and reliability characteristics of FinFET were comprehensively studied in this work. A higher ON-current, higher ON-/OFF-current ratio, smaller subthreshold swing (S.S.), lower gate leakage current, and better reliability characteristics in FinFETs are simultaneously achieved by a HfO2/ZrO2/HfO2 gate stack. The improvement can be attributed to its higher ${k}$ -value, fewer oxide traps, and oxygen vacancy in gate stack. A higher ON-current of FinFET can be obtained with an F-based plasma treatment, which, however, also induces a larger gate leakage current. A plasma treatment with F- and N-based ambient on gate stack is shown to obtain a higher ON-current and acceptable gate leakage in FinFET. Furthermore, a larger ON-current, higher ON-/ OFF-current ratio, and a smaller S.S. in FinFET can be achieved with a TiO2 stacked gate dielectric.