InP etching by chlorine ICP plasma for photonic crystal applications: experiments and simulations

Experimental and modeling studies concerning the etching of InP by chlorine plasma have been achieved. Chlorine plasma discharge has been analyzed using Langmuir probe. The latter allows to measure the electron density and temperature as a function of ICP reactor parameters such as RF power, chlorine flow rate and pressure. These two parameters play a crucial role in the modeling of plasma etch process because they directly affect the dissociation and ionization rate of gas into reactive species that participate in the InP etch process. In this context, a global gas phase kinetic model of chlorine plasma discharge is developed. The model allows to calculate the electron density and temperature, ion and atomic chlorine fluxes as a function of ICP reactor parameters. The gas phase parameters calculated from the kinetic model are thus injected in the 2D InP etch model as input parameters to study how the plasma parameters affect the etch profile through the mask. This multi-scale approach based on the coupling between the gas phase model and the surface model may contribute in the optimization of the ICP etch process for InP photonic crystal devices