Fabrication and heating rate study of microscopic surface electrode ion traps

We report heating rate measurements in a microfabricated gold- on-sapphire surface electrode ion trap with a trapping height of approximately 240µm. Using the Doppler recooling method, we characterize the trap heating rates over an extended region of the trap. The noise spectral density of the trap falls in the range of noise spectra reported in ion traps at room temperature. We find that during the first months of operation, the heating rates increase by approximately one order of magnitude. The increase in heating rates is largest in the ion-loading region of the trap, providing a strong hint that surface contamination plays a major role for excessive heating rates. We discuss data found in the literature and the possible relation of anomalous heating to sources of noise and dissipation in other systems, namely impurity atoms adsorbed onto metal surfaces and amorphous dielectrics.