%0 Journal Article %@ 0013-4686 %A Keeble, Lewis %A Jaccottet, Arthur %A Ma, Daryl %A Rodriguez-Manzano, Jesus %A Georgiou, Pantelis %D 2024 %F discovery:10185432 %I Elsevier BV %J Electrochimica Acta %K CMOS, Reference electrode, Electroplating, Electrochemical, Electroless %T An electroplated Ag/AgCl quasi-reference electrode based on CMOS top-metal for electrochemical sensing %U https://discovery.ucl.ac.uk/id/eprint/10185432/ %V 477 %X The integration and mass-production of reference electrodes for CMOS-based electrochemical sensing systems pose a challenge for the accessibility and commercial-viability of such devices. In this paper, a method of electroplating an Ag/AgCl quasi-reference electrode using CMOS top-metal as a base is presented for the first time. The aluminium bond-pad of a CMOS microchip was zincated, an electroless nickel immersion gold layer applied, and a thick silver layer electroplated and chemically chlorinated. The resulting reference electrode was able to provide a stable potential with a drift rate of 0.3 mV/h for up to 18 h. This validates the approach of a fully electroplated bond-pad reference electrode, which offers simplified post-processing and greater scalability of production. Further work towards an entirely electroless process is envisaged %Z © 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).