  We report room-temperature electric field noise measurements combined with
in-situ surface characterization and cleaning of a microfabricated ion trap. We
used a single-ion electric field noise sensor in combination with surface
cleaning and analysis tools, to investigate the relationship between electric
field noise from metal surfaces in vacuum and the composition of the surface.
These experiments were performed in a novel setup that integrates ion trapping
capabilities with surface analysis tools. We find that surface cleaning of an
aluminum-copper surface significantly reduces the level of electric field
noise, but the surface does not need to be atomically clean to show noise
levels comparable to those of the best cryogenic traps. The post-cleaning noise
levels are low enough to allow fault-tolerant trapped-ion quantum information
processing on a microfabricated surface trap.
