Abstract

Microfabrication of advanced ion trap chips is an essential part of engineering scalable quantum computer modules, quantum simulators and quantum sensor devices. We have developed a variety of modular fabrication processes based on silicon, diamond, sapphire and glass substrates suitable for a wide range of ion trap based devices.

The processes include advanced features like copper wire structures embedded in a diamond substrate capable of carrying extremely high current densities of 10A through a 60×30um cross section. This feature is essential for ion trap based quantum computer modules, powered by long-wavelength radiation, which is a very promising approach towards realising a scalable quantum computer architecture.

Other processes feature superconducting high-Q microwave resonators and structures capable of handling >1000V between two electrodes separated by 5um without electrical breakdown in vacuum, which are important ingredients in quantum hybrid and high performance ion trap devices respectively. Other on-chip features currently being developed include through silicon VIAs (TSVs), on-chip trench capacitors, optical fibres, RF and temperature sensors. Furthermore we are working towards multi-wafer packages using wafer bonding, MEMS fabrication and die bonding techniques. These packages incorporate features essential for scalable quantum computer modules and portable quantum sensors, including on-chip single photon detectors, compact multi-channel analogue voltage generators and cryogenic heat exchangers.

In addition I will discuss the use of microfabricated ion traps for quantum logic, quantum simulations and quantum sensing applications and the various experimental setups used at the IQT group to test and develop these.