In situ detection of RF breakdown on microfabricated surface ion traps

Abstract

Microfabricated surface ion traps are a principal component of many ion-based quantum information science platforms. The operational parameters of these devices are pushed to the edge of their physical capabilities as the experiments strive for increasing performance. When the applied radio-frequency (RF) voltage is increased excessively, the devices can experience damaging electric discharge events known as RF breakdown. We introduce two novel techniques for in situ detection of RF breakdown, which we implemented while characterizing the breakdown threshold of surface ion traps produced at Sandia National Laboratories. In these traps, breakdown did not always occur immediately after increasing the RF voltage, but often minutes or even hours later. This result is surprising in the context of the suggested mechanisms for RF breakdown in vacuum. Additionally, the extent of visible damage caused by breakdown events increased with the applied voltage. To minimize the probability for damage when RF power is first applied to a device, our results strongly suggest that the voltage should be ramped up over the course of several hours and monitored for breakdown.

Mitigating the Effects of Au-Al Intermetallic Compounds Due to High-Temperature Processing of Surface Electrode Ion Traps

“…The second is the high-voltage rf field applied to the device which is necessary to confine the ions. The high-voltage rf can lead to trap damage due to rf breakdown if the voltage is too high for the distance between the rf and ground [12], which is exacerbated if there is a thick metal coating applied to the top surface. Lastly, the devices are mounted on a package, which requires low-profile gold wire wedge bonds (Fig.…”

“…Our first investigation showed thick platinum and gold metal layers best mitigated the effects of IMC growth. However, thick metal stacks pose an issue for ion traps because they significantly reduce the electrodes gaps which increases the chance of electrical arcing due to the high voltage rf that is applied to the trap [12]. In our trap designs, the electrodes overhang a lower metal layer with vertical gaps as small as 2 µm [4].…”