Electron impact ionization loading of a surface electrode ion trap
  We demonstrate a method for loading surface electrode ion traps by electron impact ionization. The method relies on the property of surface electrode geometries that the trap depth can be increased at the cost of more micromotion. By introducing a buffer gas, we can counteract the rf heating assocated with the micromotion and benefit from the larger trap depth. After an initial loading of the trap, standard compensation techniques can be used to cancel the stray fields resulting from charged dielectric and allow for the loading of the trap at ultra-high vacuum. 
Kenneth R. Brown, Robert J. Clark, Jaroslaw Labaziewicz, Philip   Richerme, David R. Leibrandt, and Isaac L. Chuang