2D InP etching simulation under high density plasma of chlorine
- PDF / 150,666 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 77 Downloads / 197 Views
A5.62.1
2D InP etching simulation under high density plasma of chlorine A. Rhallabi, B. Liu, G. Marcos, J. P. Landesman Laboratoire des Plasmas et des Couches Minces - IMN, UMR 6502, CNRS – Université de Nantes, 2 rue de La Houssiniere 44322 Nantes, France. ABSTRACT A gas phase kinetic model of chlorine in an ICP reactor (Inductive Coupled Plasma) combined with a surface model have been developed to study the etching profile evolution of InP material. A gas phase chemistry model is used to predict the main neutral and charged specie fluxes impinging upon etched InP surface. These particle fluxes are then injected as input parameters into both a Monte-Carlo sheath model and a 2D surface model to predict the etch profile topography . The coupling between the gas kinetic model, sheath and surface models allows a direct prediction of the InP etch profile evolution versus reactor parameters (pressure, source power, Cl2 flow rate, DC bias on the substrate..). A parametric study is carried out to show the role of some plasma parameters on etch rate, anisotropy and adsorbed InP surface state by chlorine. INTRODUCTION It is commonly known that the dry etching process by plasma continues to play an important role in the development of electronic and optical devices. For example, for the development of new optical devices such as photonic crystals, the etching process is considered as the key for the good transfer of deep holes through the mask into the substrate. InP is one of the III-V materials which can be used as a substrate for photonic crystal applications [1]. In order to obtain a high etching anisotropy without any defects such as bowing and undercut [2], it is crucial to analyse how different plasma parameters affect the etch hole topography. The use of simulations can contribute to the optimisation of the etching process. In this article, we present a multi-scale simulation approach composed of three simulation modules: kinetic model for ICP (Inductive Coupled Plasma) Cl2 plasma to predict the neutral and charged specie fluxes, and a sheath model to predict the angular and energy distribution function of positive ions and surface model to calculate the 2D etch profile evolution with time. MODEL DESCRIPTION Figure 1 presents the flowchart of our etching simulator. At first the kinetic model is used to calculate the neutral and charged specie fluxes impinging upon the etched InP surface. Then, transport of positive ions Cl2+ and Cl+ through the sheath is studied using a Monte-Carlo technique. The sheath model determines the angular and energetic distribution functions of the ions. Such functions play an important role in the prediction of the etching profile anisotropy. These output parameters evaluated from both plasma kinetic and sheath models are then injected as the input parameters in the surface model to simulate the 2D etch profile evolution through the mask. The combination of these three models offers the possibility to predict self-consistently the etch topography versus etch reactor parameters such as sour
Data Loading...
