Investigation of thermal effects on FinFETs in the quasi-ballistic regime

Abstract

In this work, the thermal effects of FinFETs in the quasi-ballistic regime are investigated using the Monte Carlo method. Bulk Si nFinFETs with the same fin structure and two different gate lengths L g = 20 and 80 nm are investigated and compared to evaluate the thermal effects on the performance of FinFETs in the quasi-ballistic regime. The on current of the 20 nm FinFET with V gs = 0.7 V does not decrease with increasing lattice temperature (T L ) at a high V ds . The electrostatic properties in the 20 nm FinFET are more affected by T L than those in the 80 nm FinFET. However, the electron transport in the 20 nm FinFET is less affected by T L than that in the 80 nm FinFET. The electrostatic properties being more sensitive and the electron transport being less sensitive to thermal effects in the quasi-ballistic regime than in the diffusive regime should be considered for effective device modeling and design.

Thermal modeling of 7 nm node bulk fin-shaped field-effect transistors for device structure-aware design

“…From figure 4, the ballistic ratio of the 7 nm node goes up to about 70%, indicating that 30% of the electrons can travel using the diffusive transport inside the channel. As the channel length increases, the ballistic ratio becomes smaller due to the result of the increased electron-phonon scattering [11]. Also, to achieve a ballistic model which takes into account the result from the drift-diffusion (DD) simulation model, the saturation velocity (v sat ) and the exponent (β) must be extracted from the MC simulation and implanted again into the DD simulation model [12].…”

Calibration of drift-diffusion model in quasi-ballistic transport region for FinFETs

“…As devices scale down to the quasi-ballistic region, the carriers suffer only one or a few scattering events in the channel under a high electric field [1][2][3][4]. Quasi-ballistic transport, which strongly affects the device characteristics, has been studied using modeling and simulations [5][6][7][8][9][10][11][12][13][14].…”