A Highly Threshold Voltage-Controllable 4T FinFET with an 8.5-nm-Thick Si-Fin Channel

Highly threshold voltage (V/sub th/)-controllable four-terminal (4T) FinFETs with an aggressively thinned Si-fin thickness down to 8.5-nm have successfully been fabricated by using an orientation-dependent wet-etching technique, and the V/sub th/ controllability by gate biasing has systematically been confirmed. The V/sub th/ shift rate (/spl gamma/=-/spl delta/V/sub th///spl delta/V/sub g2/) dramatically increases with reducing Si-fin thickness (T/sub Si/), and the extremely high /spl gamma/=0.79 V/V is obtained at the static control gate bias mode for the 8.5-nm-thick Si-fin channel device with the 1.7-nm-thick gate oxide. By the synchronized control gate driving mode, /spl gamma/=0.46 V/V and almost ideal S-slope are achieved for the same device. These experimental results indicate that the optimum V/sub th/ tuning for the high performance and low-power consumption very large-scale integrations can be realized by a small gate bias voltage in the ultrathin Si-fin channel device and the orientation-dependent wet etching is the promising fabrication technique for the 4T FinFETs.