Simulation of DIBL effect in 25 nm SOI-FinFET with the different body shapes

Abstract

Short channel effects, such as DIBL are compared for SOI-FinFETs with different silicon body geometries. The original device considered was straight without narrowing at the top and a set of devices that exhibit the mentioned narrowing, up to the extreme case where the top of the gate has no surface and so the body cross-section is essentially a triangle. We have studied five different variations from the original geometry of a 25 nm gate length SOI-FinFET device with 1.5 nm thick oxide layer. The P-type channel had a doping concentration of 1015 cm 3 and n-type S/D areas are doped at concentrations of 1020 cm 3. The silicon body of the device accordingly had a height of 30 nm and a width of 12 nm. Simulation results show the source-drain barrier decreasing with increasing the upper body thickness. The DIBL effect of the considered FinFETs depends on upper body thickness, tending to increase with thicker upper body widths. Results of a comparison of two devices with different shapes but with the same cross-sectional area shows the relationship mainly depends on the shape rather than the cross-section area of the device body.