Fabrication of precision integrated capacitors

Optimization of Nb/Al-AlO x /Nb Josephson junctions through wafer-scale anodic oxidation: a systematic characterization and performance analysis

“…The electrolyte used for anodic oxidation was a mixture of ammonium pentaborate (390 g), ethylene glycol (2.56 l), and deionized water (1.76 l) [23,28,29]. Ammonium pentaborate, which provides H + , promotes the reaction [30], whereas ethylene glycol improves the ion mobility and surface flatness of the films [31,32]. The solution was magnetically stirred to fully dissolve the ammonium pentaborate and neutralize the mixture, ensuring that it was safe for the photoresist.…”