Characterization of an Integrated Flip-Chip Quantum Dot Platform for Rapid Testing of Semiconductor Qubit Materials

Recent demonstrations of high fidelity multiqubit operations in semiconductor based gated lateral quantum dot (QD) qubits are often limited by fundamental properties of the materials used. Development and optimization of semiconductor quantum materials is a necessity, however, rapid characterization techniques for both bulk and nano-scale materials properties for QD qubits are lacking, particularly for research level groups where the initial investment of fabricating semiconductor qubits is overwhelming. By developing a flip-chip QD platform that contains all the necessary circuit elements for the gating and readout of lateral QD qubits, an arbitrary material of interest could be used as the confining material without the investment of material specific fabrication techniques. A vacuum gap with a defined separation between the gates and the QD material of interest is accomplished by indium bump bonding techniques and precisely etched hard stop posts and mesas, achieving a separation of less than 100 nm with a deviation of 22 nm. Experimental results from several devices fabricated using this technique will be shown and we will discuss progress towards qubit formation and dispersive gate readout via a superconducting resonator on the gate-side flip chip.