4H Semi-insulating Silicon Carbide Membrane Microresonators

A mechanical resonator can serve as a versatile quantum bus to store and transfer quantum information between different physical degrees of freedom. A membrane resonator with embedded paramagnetic color centers allows a monolithic and compact device to couple a two-level system with a mechanical mode. Traditionally, the membrane resonator is defined by thin film deposition and subsequent removal of the underlying substrate. However, deposited or layer-transferred SiC/diamond film on silicon does not have coherent color centers, hence new fabrication technique is required. Here we report the wafer-scale fabrication of semi-insulating 4H silicon carbide membrane microresonators by using backside deep reactive ion etch. The etch chemistry allows us to selectively etch 200 μm SiC trenches to form membranes of 10 μm thick. The membranes have quality factors of 200 at atmospheric pressure and room temperature. We generate a resonant oscillating strain of 0.5 x 10^-3 at 6.3 MHz. Such level of strain will enable mechanical control of spin states.