Bottom-up feature fill, also called "superfill,'' of gold is demonstrated for the first time. Gold superfill is achieved in trenches as narrow as 60 nm, particularly relevant for interconnects on GaAs and GaN technologies. This was accomplished through the use of submonolayer coverage of a preadsorbed, deposition-rate accelerating surfactant followed by Au electrodeposition. The experimental results indicate the potential of this technologically relevant process and also support the generality of the CEAC mechanism for feature superfill and surface stabilization. (C) 2005 The Electrochemical Society.