Influence of Current Density on Orientation-Controllable Growth and Characteristics of Electrochemically Deposited Au Films

We demonstrate the controllable and preferentially <111> oriented growth of electrochemically deposited Au films in non-toxic sulfite electrolyte. To investigate the initial deposition, sub-10-nm-resolution orientation mapping of the Au thin films used as cathode was performed. On this cathode, the nucleation density and growth rate of nuclei are simultaneously modulated by tuning the pulse current density, resulting in variations in morphology, grain size and crystal orientation. These distinct textures greatly affects the characteristics of deposited Au films including Young's modulus and hardness. Furthermore, the interpretation is made for describing the formation of different microstructures in three cases. At an appropriate current density, the appropriate density of nuclei and the subsequent growth lead to preferential growth at <111> orientation and suppression of growth at other orientations. The results presented in this work would be beneficial to wide applications of Au electrochemical deposition in sulfite electrolyte. (c) The Author(s) 2018. Published by ECS.