International Business Machines Corporation
Vertical FET with asymmetric threshold voltage and channel thicknesses

Abstract:

An FET comprises a source, a drain, a channel, and a gate encompassing the channel. The channel has a first region that is thinner than in a second region. The Threshold Voltage, Vth, is larger in the first region than in the second region causing an asymmetric Vth across the length of the channel. Modeling has shown that the Vth increases along the channel from about 50 milliVolts (mV) for N-FETs (about 55 mV for a P-FETs) to about 125 mV for N-FETs (about 180 mV for P-FETs) as the channel width decreases from 4 nanometers (nm) to 2 nm.