Fabrication of low grass, smooth sidewall InGaAsP by methane–hydrogen inductively coupled plasma RIE through a metal lift-off mask patterned by e-beam lithography

An optimized CH4+H2 inductively coupled-plasma reactive-ion-etching process for fabrication of high quality nanophotonic InGaAsP/InP waveguide device has been developed. Important parameters that influence e-beam lithography and etching have been optimized for a simple metal lift-off masked process. Smooth sidewalls with low grass content has been demonstrated for >3 μm etch depths in InGaAsP/InP using an Al lift-off etch mask.