Discrete-dopant-fluctuated threshold voltage roll-off in sub-16 nm bulk fin-type field effect transistors

Abstract

The effect of the number and position of discrete dopants on device characteristics is crucial in determining the behavior of nanoscale semiconductor devices. We explore the fluctuations of threshold voltage (V(th)) roll-off in nanoscale bulk fin-type field effect transistors (FinFETs) by a three-dimensional (3D) statistically full-scale "atomistic" device simulation technique. The explored devices are of three different dimensions: 16, 22, and 30 nm(3). Discrete dopants are statistically positioned into the 3D channel region to explore associated carrier transport characteristics, concurrently capturing "dopant concentration variation" and "dopant position fluctuation". For the device with a gate length of 16 nm, the V(th) fluctuation of FinFETs is only half that of planar metal-oxide-semiconductor (MOS) FET. Compared with planar MOSFETs, the bulk FinFETs can significantly suppress the fluctuation of V(th) roll-off. The standard deviation of V(th) is proportional to (WL)(-0.25), which is better than the (WL)(-0.5) of planar devices. The superior immunity against fluctuation and the stable fluctuation of V(th) roll-off indicate the bulk FinFET to be a promising device for the sub-16 nm technology era.