A silicon-based ion trap chip protected from semiconductor charging

TL;DR

This paper presents a silicon-based ion trap chip with gold coating on exposed surfaces, significantly reducing semiconductor charging effects and enabling advanced quantum operations.

Contribution

The study introduces a novel gold coating technique on silicon ion traps to mitigate charging, enhancing stability and quantum operation feasibility.

Findings

Gold coating stabilizes ion motion

Background silicon-induced fields are negligible

Enables complex quantum operations

Abstract

Silicon-based ion trap chips can benefit from existing advanced fabrication technologies, such as multi-metal layer techniques for two-dimensional architectures and silicon photonics for the integration of on-chip optical components. However, the scalability of these technologies may be compromised by semiconductor charging, where photogenerated charge carriers produce electric potentials that disrupt ion motion. Inspired by recent studies on charge distribution mechanisms in semiconductors, we developed a silicon-based chip with gold coated on all exposed silicon surfaces. This modification significantly stabilized ion motion compared to a chip without such metallic shielding, a result that underscores the detrimental effects of exposed silicon. With the mitigation of background silicon-induced fields to negligible levels, quantum operations such as sideband cooling and two-ion entangling gates, which were previously infeasible with the unshielded chip, can now be implemented.