Medici simulations of ion beam irradiated silicon under anodization

Abstract

Ion beam irradiation and anodization of silicon wafers are the two basic processes involved in patterned porous silicon formation and silicon micromachining. The damages introduced by ion irradiation influence the flow of holes during anodization and enables patterning. The exact physics of this influence is not well known. A simulation study of the processes involved is presented here.The ion-damaged regions are simulated in Medici TCAD software by introducing electron and hole trap states in defined volumes of the structure. The simulated irradiated wafers are studied in an equilibrium state at the very beginning of anodization.Basic simulations are made, and influence of experimental parameters such as wafer resistivity or ion dose are studied. From these observations a possible physical origin of the ion-damage effects on hole flow is discussed. Further experiment-related studies (feasibility, improvement) have been made in both patterned photoluminescence and micromachining fields, on gratings and multiple dose structures.