Si/SiGe heterostructures on bulk Si substrates have been shown to host high fidelity electron spin qubits. Building a scalable quantum processor would, however, benefit from further improvement of critical material properties such as the valley-splitting landscape. Flexible control of the strain field and the out-of-plane electric field Ez may be decisive for valley splitting enhancement in the presence of alloy disorder. We envision the Si/SiGe membrane as a versatile scientific platform for investigating intervalley scattering mechanisms which have thus far remained elusive in conventional Si/SiGe heterostructures and have the potential to yield favourable valley-splitting distributions. Here, we report the fabrication of locally etched, suspended SiGe/Si/SiGe membranes from two different heterostructures and apply the process to realize a spin-qubit shuttling device on a membrane for future valley mapping experiments. The membranes have a thickness in the micrometer range and can be metallized to form a back-gate contact for extended control over the electric field. To probe their elastic properties, the membranes are stressed by loading with a profilometer stylus at room temperature. We distinguish between linear elastic and buckling modes, each offering mechanisms through which strain can be coupled to spin qubits.
@article{arxiv.2508.14589,
title = {Fabrication, characterization and mechanical loading of Si/SiGe membranes for spin qubit devices},
author = {Lucas Marcogliese and Ouviyan Sabapathy and Rudolf Richter and Jhih-Sian Tu and Dominique Bougeard and Lars R. Schreiber},
journal= {arXiv preprint arXiv:2508.14589},
year = {2026}
}