Atomistic Simulation of Modulus Deficit in Thin Film Copper Electrodeposits
Abstract
Inconsistencies of the measured value of the Youngs modulus, between microtensile values and bulk values for metal thin films, have been reported by multiple investigators. The microtensile values are typically lower than the bulk values by ten percent or more; this phenomenon has been called the modulus deficit in thin films. Recent experimental observations on thin film copper electrodeposits showed a complex, fine-scale morphology, with a smaller scale than the grain size. The film appeared to be composed of an agglomeration of near-spherical clusters of copper atoms. Here, molecular dynamics results on the elastic behavior of copper nanorods and chains of nanospheres are presented. The differences from bulk behavior in the sphere models are in the same direction as, and larger than, the observed modulus deficit. For instance, the <110> chains-of-spheres had a Youngs modulus of about 0.7 times the bulk value. The most visible disorder created by the present process of joining perfect-crystal spheres has the appearance of grain boundaries.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARJ32001R