Pulsed Current Plating Does Not Improve Microscale Current Distribution Uniformity Compared to Direct Current Plating at Equivalent Time-Averaged Plating Rates

Abstract

Suppression of surface roughness and dendrite growth under pulsed current (p.c.) plating is a widely reported effect for a variety of electrodeposited metals. Often, this effect is attributed to the modulation of mass transport during pulsing. In the present contribution, we use numerical simulations and scaling analysis to shed light on the transient mass transport effects near a 2D microscale pattern subjected to p.c. plating. Specifically, we compare the microscale current distribution during p.c. to that during direct current (d.c.) plating at an equivalent time-averaged plating rate. Modeling shows that the more uniform current distribution for a given time-averaged plating rate is that obtained during d.c. plating. The current distribution during p.c. plating is found to be less uniform in comparison to d.c., and the mechanistic rationale underlying this effect is explained using scaling analysis. Results reported herein have implications to the understanding of pulsed currents in applications ranging from thin-film electroplating to battery charging.