Gold cleaning methods for electrochemical detection applications
By Fischer, Lee M.; Tenje, Maria; Heiskanen, Arto R.; Masuda, Noriyuki; Castillo, Jaime; Bentien, Anders; Émneus, Jenny; Jakobsen, Mogens H. & Boisen, Anja
Published in Microelectronic Engineering
2009
Abstract
This work investigates methods for obtaining reliably clean gold film surfaces. Nine gold cleaning methods are investigated here: UV ozone photoreactor; potassium hydroxide–hydrogen peroxide; potassium hydroxide potential sweep; sulfuric acid hydrogen peroxide; sulfuric acid potential cycling; hydrochloric acid potential cycling; dimethylamine borane reducing agent solutions at 25 and 65 °C; and a dilute form of Aqua Regia. Peak-current potential-differences obtained from cyclic voltammetry and charge transfer resistance obtained from electrochemical impedance spectroscopy, as well as X-ray photo-electron spectroscopy are used to characterize surface cleanliness. A low peak-current potential-difference and charge transfer resistance indicates a cleaner surface, as does a higher percentage of elemental gold on the electrode surface. The potassium hydroxide potential sweep method is found to leave the gold surface the cleanest overall.