A functional 41-stage ring oscillator using scaled FinFET devices with 25-nm gate lengths and 10-nm fin widths applicable for the 45-nm CMOS node

We have fabricated a functional FinFET ring oscillator with a physical gate length of 25 nm and a fin width of 10 nm, the smallest ever reported. We demonstrate that these narrow (W/sub fin/ = 10 nm) and tall (H/sub fin/ = 60 - 80 nm) fins can be reliably etched with controlled profiles and that they are required to keep the short-channel effects under control, resulting in drain-induced barrier leakage characteristics of 45 mV/V at V_DD = 1 V and L/sub g/ = 25 nm for the nFET. For these ultrathin (10 nm) fins, we have succeeded in properly setting the V_T at 0.2 V without the use of metal gates. In addition to ring oscillators, we also have obtained excellent pFET FinFET devices at wider fin widths (W/sub fin/ = 65 nm) with I/sub dsat/ = 380 μA/μm at I/sub off/ = 60 nA/μm and V_DD = -1.2 V.