Stress Evolution During Electrochemical Deposition of Thin Films

Abstract

Format

This is a copy of the slides presented at the meeting but not formally written up for the volume.

Abstract

The stress evolution during electrochemical deposition of metals on amorphous substrates was monitored by an in situ, real time cantilever curvature measurement technique. The technique used is similar to that employed for in situ stress measurements performed during physical vapor deposition of thin films, but has been modified for optimal use in an electrochemical system. The electrodeposited films displayed Volmer-Weber island growth behavior, and exhibited a compression-tension-compression stress development that could be correlated with discrete island formation, island-coalescence, and post-coalescence growth stages, respectively. Under constant current conditions, the voltage transient displayed a corresponding three-stage character. Atomic force microscopy images confirmed that the microstructures of the films underwent three-dimensional island nucleation and growth. In the post-coalescence regime, interruption of the deposition resulted in an exponentially decreasing stress relaxation. The overall stress behaviors during growth and after the growth interruption were found to be very similar to that observed during physical vapor deposition of films on amorphous substrates. The experimental results will be analyzed in terms of recently proposed stress generation mechanisms.