Numerical 2D/3D modeling of surface ionization wave propagating in air over silicon

Abstract

In this study, we present a 2D/3D fluid model to simulate the propagation of a surface ionization wave (SIW) in air at atmospheric pressure, initiated by a wire electrode placed in contact with a SiO2 layer deposited on a p-doped silicon wafer, which is in turn in contact with glass placed over the ground. Thus, instead of studying a classical dielectric barrier discharge, we focus here on a new type of discharge: the semiconducting barrier discharge. The model couples a drift-diffusion model in both air and silicon to resolve the temporal evolution of charged species: electrons, positive ions, and negative ions in air, as well as mobile electrons, holes, and immobile charges in silicon. Simulation results were validated against experimental data, including time-resolved imaging and current measurements, for doping levels of the p-doped silicon corresponding to resistivities of 3000, 40, and 10 Ω·cm. Using the 2D model, we demonstrate that higher doping levels lead to faster SIW ignition, driven by charge reorganization in silicon that enhances the electric field (E-field) in air. From 3000 to 40 Ω·cm, increased doping also promotes confinement of the SIW toward the SiO2–Si interface and increases photoelectron generation. However, increasing the doping further to 10 Ω·cm results in excessive confinement, which limits photoelectron production. Additionally, higher doping levels yield increases SIW current, attributed to greater charge density generated by the enhancement of the E-field component normal to the SiO2–Si interface. Extending the model to 3D reveals that doped silicon promotes uniform SIW propagation by enhancing photon-induced ionization, mitigating instabilities arising from the stochasticity of photoelectron production.