Extremely-Low Threshold Voltage FinFET for 5G mmWave Applications

Abstract

An optimized doping process is used to achieve extremely-low threshold voltage (ELVT) FinFETs for low-power mmWave applications based on 12nm node technology platform. With the $V_{TH}\approx 100$ mV ELVT FinFET shows 15% $I_{EFF}$ improvement at the same $V_{DD}$ compared to its super-low threshold voltage (SLVT) counterpart, while mismatch and reliability performances are comparable. $F_{T}/F_{MAX}$ of ~305GHz/~315GHz and comparable Maximum Stable Gain (MSG) to SLVT FinFET gives ELVT FinFET an advantage for mmWave 5G low-power applications. Local oscillator (LO) chain blocks are investigated as a circuit level example to confirm the benefits of ELVT FinFET. An optimized LO transmission Line (TL) driver using ELVT FinFETs results in ~9% and ~8% reduction in $V_{DD}$ and power consumption respectively at the same phase-noise (PN) level as the SLVT based design. If operated at the same $V_{DD}$ of 0.525V ELVT FinFET can improve the VCO Figure of Merit ( $FOM_{VCO}$ ) by ~2.8dB.

Keywords

• FinFET
• extremely-low threshold voltage
• radio frequency
• 5G
• RF
• mmwave