Paper PS-TuA12
Modeling of InP Etching under High Density Plasma of Cl₂/Ar

Tuesday, October 21, 2008, 5:20 pm, Room 304

It is now evident that the improvement of the optical and electrical performances of the III-V components depends on the optimization of the critical process steps such as the dry etch processes especially for the submicron devices. The simulation of plasma surface interaction may widely contribute to the optimization of such process type. In the present study, a gas phase kinetic model of Cl2/Ar plasma combined to surface model is developed to predict the etching profiles as a function of the plasma parameters. The gas phase kinetic model is based on the mass balance equations of reactive species. The kinetic constants of electron impact reactions are established as a function of electron temperature assuming maxwellian distribution of electron energy. The additional equation of power balance in the ICP reactor allows to determine the electron temperature evolution with the plasma discharge parameters (Rf power, reactor pressure and the chlorine flow rate). Parametric studies concerning the effects of the plasma parameters like power, pressure and percentage of Cl2 on the transport of charged and neutral specie evolutions have been carried out. On the other hand, the simulation results show that electron density and the dissociation rate of Cl2 are more sensitive to the surface recombination coefficient of atomic chlorine. The later is estimated at 0.15. Langmuir probe is used to measure the electrical parameters of Cl2/Ar plasma mixture such as, electron temperature and density as a function of the plasma discharge parameters. A satisfactory agreements between the simulations and the experiments have been observed One of the advantage of our model is the coupling between the plasma chemistry model and the surface etching model. The later is based on the Monte-Carlo approach which allows to describe, in a probabilistic manner, the surface mechanisms for InP etching . The direct fluxes of the reactive species such as Ar+, Cl2+, Cl+ and Cl are determined from the gas phase kinetic model and introduced as the input parameters in the InP etching model. The simulation results show the role of different plasma parameters on the etched surface profiles.