Industrially Microfabricated Ion Trap with 1 eV Trap Depth

TL;DR

This paper introduces a scalable microfabrication process for 3D ion traps with a trap depth of 1 eV, suitable for large-scale quantum computing with ions.

Contribution

The authors demonstrate a novel MEMS microfabrication technique to produce reproducible, large-volume 3D ion traps with high trap depth and precise alignment.

Findings

Achieved a trap depth of 1 eV for calcium-40 ions at 200 micrometers from electrodes.

Measured motional heating rates of 40 phonons/sec at 1 MHz and 185 K.

Characterized trap frequencies with +/-5% agreement between measurements and simulations.

Abstract

Scaling trapped-ion quantum computing will require robust trapping of at least hundreds of ions over long periods, while increasing the complexity and functionality of the trap itself. Symmetric 3D structures enable high trap depth, but microfabrication techniques are generally better suited to planar structures that produce less ideal conditions for trapping. We present an ion trap fabricated on stacked 8-inch wafers in a large-scale MEMS microfabrication process that provides reproducible traps at a large volume. Electrodes are patterned on the surfaces of two opposing wafers bonded to a spacer, forming a 3D structure with 2.5 micrometer standard deviation in alignment across the stack. We implement a design achieving a trap depth of 1 eV for a calcium-40 ion held at 200 micrometers from either electrode plane. We characterize traps, achieving measurement agreement with simulations to within +/-5% for mode frequencies spanning 0.6--3.8 MHz, and evaluate stray electric field across multiple trapping sites. We measure motional heating rates over an extensive range of trap frequencies, and temperatures, observing 40 phonons/s at 1 MHz and 185 K. This fabrication method provides a highly scalable approach for producing a new generation of 3D ion traps.