Random Dopant-Induced Variability in Si-InAs Nanowire Tunnel FETs: A Quantum Transport Simulation Study

Abstract

In this letter, we report a quantum transport simulation study of the impact of random discrete dopants (RDDs) on Si-InAs nanowire p-type Tunnel FETs. The bandto-band tunneling is simulated using the non-equilibrium Green's function formalism in effective mass approximation, implementing a two-band model of the imaginary dispersion. We have found that RDDs induce strong variability not only in the OFF-state but also in the ON-state current of the TFETs. Contrary to the nearly normal distribution of the RDD-induced ON-current variations in conventional CMOS transistors, the TFET's ON-currents variations are described by a logarithmic distribution. The distributions of other figures of merit (FoM) such as threshold voltage and subthreshold swing are also reported. The variability in the FoM is analyzed by studying the correlation between the number and the position of the dopants.

Simulation and Modeling of Novel Electronic Device Architectures with NESS (Nano-Electronic Simulation Software): A Modular Nano TCAD Simulation Framework

“…It is possible to consider dissipative transport by switching on the acoustic or optical phonon scattering to enable electron-phonon (e-ph) interactions within the self-consistent Born approximation (SCBA) or neglect them to investigate the purely ballistic transport [36][37][38]. Moreover, the NEGF solver implemented in NESS allows to simulate 2D planar structures, such as DGSOI [39], and to calculate the BTBT by using the Flietner model to compute the current in heterostructures with a direct bandgap [40]. A combination of this NEGF module with a full-band quantum transport solver in presence of hole-phonon interactions using a mode-space k•p approach has been also implemented [41].…”

“…Few analytical models exist in the literature to compute the BTBT accounting for quantum effects, which are commonly implemented in semi-classical tools based on the Wentzel, Kramers, and Brillouin (WKB) approximation [66][67][68]. In NESS, it is possible to compute the direct BTBT in nanodevices making use of the coupled mode-space NEGF scheme within the effective mass approximation (EMA) and the Flietner model of the imaginary dispersion [40].…”

A Study on the Effect of the Structural Parameters and Internal Mechanism of a Bilateral Gate-Controlled S/D Symmetric and Interchangeable Bidirectional Tunnel Field Effect Transistor

“…Meanwhile, the introduction of two-dimensional materials into TFETs as tunneling layers with ultrathin thickness has been extensively studied [39][40][41][42][43][44]. In addition, some papers have reported the reliability of TFETs, such as the effect of source doping on tunneling band gap interleaving [45], the effect of trap-assisted tunneling on the subthreshold characteristics of TFETs [46], and the effect of random doping on the device performance perturbation [47]. However, the current research results mainly aim at the basic working characteristics and working principles of single TFETs, and the most important fundamental purpose of the research and development of TFETs is to provide a basic structural unit with lower power consumption and replace the existing MOSFET structure.…”

Enhanced Capabilities of the Nano-Electronic Simulation Software (NESS)

“…This solver can consider phonon scattering in addition to the transport in the ballistic limit. Furthermore, the NEGF solver implemented in NESS allows the calculation of band-to-band tunneling (BTBT) by using the Flietner model to compute the current in heterostructures with direct band gap [10] and the study of surface roughness (SR) scattering mechanism [11]. Finally, the simulation results are stored in text files (i.e.…”