Performance and reliability of sub-100 nm MOSFETs with ultra thin direct tunneling gate oxides

In this paper, we report the performance and reliability of sub-100 nm MOSFETs with ultra thin direct tunneling (DT) gate oxides. Both pure oxides and nitrided oxides down to 17 Å were investigated. For a L/sub g/ of about 90 nm (L/sub eff/ of about 50 nm), a drive current of larger than 1.0 mA/μm and a transconductance of higher than 800 mS/mm were obtained at room temperature. Channel electron transport properties were investigated. High field mobility degradation with decrease of oxide thickness and subsequent improvement with use of nitrided oxides were observed. Reliability characteristics such as gate leakage, stress-induced-leakage, and hot-carrier degradation are described. A new mechanical stress induced leakage phenomenon for ultra thin DT oxides was revealed.