Ab initio Study of Metal Grain Orientation-Dependent Work Function and its Impact on FinFET Variability

Author

Agarwal, Sankalp ; Pandey, Rajan K. ; Johnson, J.B. ; Dixit, Abhishek ; Bajaj, Mohit ; Furkay, Stephen S. ; Oldiges, Philip J. ; Murali, Kota V. R. M.

Author_Institution

Semicond. R&D Center, IBM, Bangalore, India

Volume

60

Issue

9

fYear

2013

fDate

Sept. 2013

Firstpage

2728

Lastpage

2733

Abstract

A novel method to model the effect of local workfunction variation in high-k metal gate nanoscale transistors is proposed. Impact of variability in metal grain granularity on device performance is studied using ab initio density functional theory calculations and device simulations, which show that different metal grain orientations (GOs) can result in large (≥100 mV) variation in metal gate effective work function. Probabilities of occurrence of each GO and the grain size are used to estimate the work-function variations. Full 3-D device simulations are performed to study the effect of metal grain granularity on FinFET and planar MOSFET behavior. Simulated mismatch trends are shown to be in good agreement with the grain diameters and device geometries.

Keywords

MOSFET; density functional theory; nanoelectronics; semiconductor device models; 3D device simulations; FinFET variability; ab initio density functional theory calculations; device geometry; device performance; grain diameters; grain size; high-k metal gate nanoscale transistors; local workfunction variation; metal gate effective work function; metal grain granularity; metal grain orientation-dependent work function; metal grain orientations; planar MOSFET behavior; simulated mismatch; work-function variations; FinFETs; Hafnium compounds; Logic gates; Threshold voltage; Tin; FinFET; metal grain granularity (MGG); threshold voltage; work function;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2013.2272998

Filename

6566015