Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 6: Materials and Devices for Quantum Technology I
HL 6.10: Vortrag
Montag, 17. März 2025, 17:30–17:45, H13
Fabrication, characterization and deformation of Si/SiGe membranes for spin qubit devices — •Lucas Marcogliese1, Ouviyan Sabapathy1, Rudolf Richter2, Dominique Bougeard2, and Lars R. Schreiber1,3 — 1JARA-FIT Institute for Quantum Information, Aachen, Germany — 2University of Regensburg, Regensburg, Germany — 3ARQUE Systems GmbH, Aachen, Germany
The energy separation between the two lowest lying energy states in silicon, known as valley splitting, has been shown to have a significant impact on dephasing times, readout and shuttling fidelities of spin qubits in Si/SiGe. Greater control over the strain tensor field may be decisive for deterministic valley splitting enhancement in the presence of alloy disorder. Here, we demonstrate the fabrication of SiGe/Si/SiGe quantum well membranes suspended by the handle wafer via wet etching. Relying on SiGe as an etch stop, the robust and reproducible process yields membranes down to micrometer thicknesses. Raman maps confirm that etching preserves epitaxial tensile strain in the quantum well. Remarkably, they reveal that the in-plane strain components generated by the cross-hatch pattern typical of Si/SiGe heterostructures on bulk substrates disappear on etched membranes. To probe their elastic properties, the membranes are stressed by loading with a profilometer stylus at room temperature. We envision the Si/SiGe membrane as a flexible scientific platform for investigating novel, advanced valley splitting enhancements techniques, required for scalable Si/SiGe quantum computing with electron spins.
Keywords: Si/SiGe heterostructure; Membrane; Fabrication; Strain; Spin qubits