Dry etching for Germanium waveguides by using CHF3 inductively coupled plasma

Dry etching for Ge waveguide has been researched by using inductively coupled plasma technique with CHF₃ gas. It realizes a high selectivity of 5:1 against regular photoresist mask. Moreover, anisotropic etching without under-cut has been successfully realized with an etched siclewall angle of 85 degree with an etching rate of 190 nm/min.