Silicon Vibrating Micro-Wire Resonators for Study of Quantum Turbulence in Superfluid 4He

We report a fabrication process and characterization measurements of single crystal silicon micro-wire resonators to be used for study of quantum turbulence in superfluid 4 He at millikelvin temperatures. Our devices are single standing goal-post-shaped silicon structures with a width and height of the order of 7 microns. Vapour-deposited superconducting aluminium film of 120 nm thickness is used for magneto-motive drive of the resonators. In the window of each chip, two such devices of different dimensions are placed 30 µm to 1 mm apart, with the intent to study interaction due to pinned quantized vortices. With resonant frequencies below 10 kHz, the devices reach quality factors of ≈ 2 × 10 4 in cold helium vapour.