| AVS 58th Annual International Symposium and Exhibition | |
| Plasma Science and Technology Division | Friday Sessions |
| Session PS-FrM |
| Session: | Plasma Modeling |
| Presenter: | Ahmed Rhallabi, Institut des Matériaux Jean Rouxel (IMN), France |
| Authors: | R. Chanson, Institut des Matériaux Jean Rouxel (IMN), France A. Rhallabi, Institut des Matériaux Jean Rouxel (IMN), France M.C. Fernandez, Institut des Matériaux Jean Rouxel (IMN), France Ch. Cardinaud, Institut des Matériaux Jean Rouxel (IMN), France J.P. Landesman, Institut des Matériaux Jean Rouxel (IMN), France S. Bouchoule, Laboratoire de Photonique et de Nanostructures (LPN), France A. Talneau, Laboratoire de photonique et de Nanostructures (LPN), France |
| Correspondent: | Click to Email |
InP-based optoelectronic devices need reliable dry etching processes characterized by high etch rate, profile control and low damages. High density plasma etching, using inductively coupled plasma ICP reactors, has been found to be very important for the transfer of patterns from the mask to InP substrate and InP-based layers. In order to investigate the role of N2 in the InP etching process under Cl2/Ar/N2 plasma discharge, we have developed an InP etching simulator permitting to determine the InP etch profile evolution through the mask as a function of the operating conditions and the initial mask geometry.
The InP etching simulator is divided in three modules: the global kinetic model of Cl2/Ar/N2 ICP plasma discharge is based on 0D approach which allows to calculate the averaged densities of neutrals and ions as well as the electron density and electron temperature versus the machine parameters. The resolution of the differential equations associated to the mass balance of each considered specie coupled to charge neutrality equation and the differential power balance equation from t=0 until the steady state allows to determine all reactive specie densities as well as their fluxes into the InP substrate. ne and Te calculated from the plasma global kinetic model are introduced in the sheath model to estimate the average sheath thickness. The Monte-Carlo technique is used to study the ion transport in the sheath. The calculation of energies and angles of all positive ions impinged on the substrate allows determining the angular and energy distribution functions of positives ions. Such distribution functions with Cl, N and positives ions fluxes are introduced as input parameters into the etching model. The later is based on the cellular approach combined to the Monte-Carlo method which the considered domain (InP substrate and mask) is discretized on 2D uniform cells which each cell represents a real number of In sites. The fluxes of neutral species and positive ions are introduced as input parameters into the etching model. All the particle surface interaction processes like adsorption of atomic neutrals Cl and N on InClxNy surface sites, desorption of InClx sites, sputtering of both InClxNy and mask by positive ions and redeposition of InClx sites are described in probabilistic ways. Simulation results show the effect of the N2 on the passivation of the lateral surfaces and as consequence the improvement of the etch profile anisotropy. However, a diminution of the etch rate by increasing the percentage of N2 is observed. The simulated etch profiles are compared to those obtained by the experiments and the good agreements are obtained.