Hybrid Diamond/Silicon Suspended Integrated Photonic Platform using SF6 Isotropic Etching

A hybrid diamond/silicon air-clad ridge waveguide platform is demonstrated. The air-clad structure coupled with the wide transmission window of diamond can allow for the use of this architecture over a large wavelength range, especially for the longer infrared wavelengths. In order to provide vertical confinement, the silicon substrate was isotropically etched using S
F6
plasma to create undercut diamond films. An in-depth analysis of the etch characteristics of this process was performed to highlight its potential to replace wet isotropic etching or XeF
2
isotropic vapour phase etching techniques. The performance of the waveguide at 1550 nm was measured, and yielded an average loss of 4.67 +/- 0.47 dB/mm.