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.
Viswas Sadasivan, Dagar, S., and Das, U., “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”, Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society, vol. 33, p. 051210, 2015.