Discrete-dopant-induced characteristic fluctuations in 16 nm multiple-gate silicon-on-insulator devices

The impact of the number and position of discrete dopants on device characteristics is crucial in determining the behavior of nanoscale semiconductor devices. This study explores discrete-dopant-induced characteristic fluctuations in 16nm single-, double-, triple-, and (square shape) surrounding-gate silicon-on-insulator (SOI) devices. Discrete dopants are statistically positioned in the three-dimensional channel region to examine associated carrier transportation characteristics, concurrently capturing "dopant concentration variation" and "dopant position fluctuation." An experimentally validated simulation was conducted to investigate the threshold voltage (V_th) fluctuation and the variation of the on- and off-state currents of the four explored structures. The fluctuations of V_th of the double-, triple- and surrounding-gate devices are 2.2, 3.3 and 4 times smaller, respectively, than that of planar SOI. Results of this study provide further insight into the problem of fluctuation and the mechanism of immunity against fluctuation in ultrasmall field effect transistors (FETs) with vertical channel structures, such as fin-typed FETs.