Estimating Electrodeposition Properties and Processes: Cu-Ag Alloy at n-Si(001) and Ru Substrates from Acidic Sulfate Bath

Abstract

A simple method for estimating the composition and duration of the initial stage of alloy electrodeposition is important for deposition process design and the deposit characterization. Analytically or numerically solving the complete diffusion-migration-convection problem based on common simulation methods could be difficulty to be implicated as an ordinary task for designing alloy electrodeposition parameters and electrolytes.In this work, we have proposed some simple estimations for the initial stage of Cu-Ag alloy electrodeposition, at Si(001) or polycrystalline Ru, regarding (1) the potential-composition curve, (2) the thickness of the initial deposit, and (3) the time interval to reach the steady state deposition, based on the stagnant diffusion layer model. The limiting deposition current is compared with the numerical results from Selman and Newman in 1970s [1]. Meanwhile, composition of the film deposited under limiting current with various electrolyte chemistries is compared with the model suggest by Brenner [2]. Despite the model proposed in this work are highly simplified and not precisely realistic, estimated values show good agreement with the observed values. Reference: [1] J.R. Selman, J. Newman, Migration in Supported Electrolyte Solutions with Free Convection, (1971).[2] A. Brenner, 11 The Role of the Cathode Diffusion Layer in the Electrodeposition of Alloys, in: A. Brenner (Ed.) Electrodeposition of Alloys, Academic Press1963, pp. 307-330. Disclaimer: This work has been published at Electrochimica Acta, 403:139695 with title "Estimating electrodeposition properties and processes: Cu-Ag alloy at n-Si(001) and Ru substrates from acidic sulfate bath". Figure attached is chosen from this manuscript. Figure (a) Observed and estimated composition-potential curve for Cu-Ag electrodeposition system. (b) Film thickness v.s. deposition time, and (c) film thickness v.s. composition of the film, from which Ag-rich initial deposit was observed. Figure 1