Anisotropic Quantum Corrections for 3-D Finite-Element Monte Carlo Simulations of Nanoscale Multigate Transistors

Muhammad A Elmessary,Manuel Aldegunde,Djordje Peric,Wulf G Dettmer,Karol Kalna,Jari Lindberg,Daniel Nagy,Antonio J Garcia-Loureiro

doi:10.1109/ted.2016.2519822

Abstract

Anisotropic 2-D Schrodinger equation-based quantum corrections dependent on valley orientation are incorporated into a 3-D finite-element Monte Carlo simulation toolbox. The new toolbox is then applied to simulate nanoscale Si Silicon-on-Insulator FinFETs with a gate length of 8.1 nm to study the contributions of conduction valleys to the drive current in various FinFET architectures and channel orientations. The 8.1 nm gate length FinFETs are studied for two cross sections: rectangular-like and triangular-like, and for two channel orientations: $\langle 100\rangle $ and $\langle 110\rangle $ . We have found that quantum anisotropy effects play the strongest role in the triangular-like $\langle 100\rangle $ channel device increasing the drain current by $\sim 13$ % and slightly decreasing the current by 2% in the rectangular-like $\langle 100\rangle $ channel device. The quantum anisotropy has a negligible effect in any device with the $\langle 110\rangle $ channel orientation.

Highlights

M ULTIGATE nonplanar FETs are leading solutions for sub-14 nm technology nodes because of their exceptional electrostatic integrity [1], [2]
We report on anisotropic FE Schrödinger equation-based quantum corrections (QCs) incorporated into in-house 3-D FE Monte Carlo (MC) device toolbox [5], [6]
A new anisotropic QC using the solutions of 2-D FE Schrödinger equation on the slices along the channel of multigate transistors has been incorporated into the 3-D FE MC device toolbox [6]

Summary

INTRODUCTION

M ULTIGATE nonplanar FETs are leading solutions for sub-14 nm technology nodes because of their exceptional electrostatic integrity [1], [2]. The MC transport engine has already included anisotropic bandstructure [6]–[8] using k-vector transformations [9], but the Schrödinger equation QCs were approximated by isotropic electron effective mass tensor (EMT) [5]. The 3-D FE MC simulation toolbox with the 2-D Schrödinger equation-based QCs [5] used an isotropic (scalar) effective mass This implies that the same quantum potential is seen by all the particles independently of the orientation of valleys neglecting, the confinement-induced valley splitting [5], [12]. The separate QCs for each valley accurately account for quantum confinement in nanoscale nonplanar Si channels, and have diverse effects in various device cross sections and channel orientations. Where t denotes time and k is the wave vector of the particle

APPLICATION TO NANOSCALED Si SOI FinFETs

Findings

CONCLUSION