A first-principles analysis of ballistic conductance, grain boundary scattering and vertical resistance in aluminum interconnects

We present an ab initio evaluation of electron scattering mechanisms in Al interconnects from a back-end-of-line (BEOL) perspective. We consider the ballistic conductance as a function of nanowire size, as well as the impact of surface oxidation on electron transport. We also consider several repres...

Full description

Saved in:
Bibliographic Details
Published in:AIP advances 2018-05, Vol.8 (5), p.055127-055127-9
Main Authors: Zhou, Tianji, Lanzillo, Nicholas A., Bhosale, Prasad, Gall, Daniel, Quon, Roger
Format: Article
Language:English
Subjects:
Aluminum
Copper
Diffusion barriers
Electromigration
Electron transport
First principles
Grain boundaries
Interconnections
Mathematical analysis
Nanowires
Oxidation
Resistance
Scattering
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We present an ab initio evaluation of electron scattering mechanisms in Al interconnects from a back-end-of-line (BEOL) perspective. We consider the ballistic conductance as a function of nanowire size, as well as the impact of surface oxidation on electron transport. We also consider several representative twin grain boundaries and calculate the specific resistivity and reflection coefficients for each case. Lastly, we calculate the vertical resistance across the Al/Ta(N)/Al and Cu/Ta(N)/Cu interfaces, which are representative of typical vertical interconnect structures with diffusion barriers. Despite a high ballistic conductance, the calculated specific resistivities at grain boundaries are 70-100% higher in Al than in Cu, and the vertical resistance across Ta(N) diffusion barriers are 60-100% larger for Al than for Cu. These results suggest that in addition to the well-known electromigration limitations in Al interconnects, electron scattering represents a major problem in achieving low interconnect line resistance at fine dimensions.
ISSN:2158-3226
2158-3226
DOI:10.1063/1.5027084