Simulation of 3D Doping by Plasma Immersion Ion Implantation for FinFET or deep Trench Doping Applications. Effect of main Process Parameters and Study of Wall Doping Non-Uniformity as Function of Form Factor and Device Scaling

Abstract

Understanding and simulating 3D doping performed by Plasma Immersion Ion Implantation on FinFETs or on deep trenches for flash memories or power devices applications is a key topic to optimize process parameters and to forecast effect of form factor evolution requested by technology scaling. In this work, we developed a model based on the following strategy.1-Calculation of angle and energy distribution of ions and neutrals reaching wafer surface as function of PIII process parameters (TRIM Monte Carlo simulation in gases)2-Calculation of local ion distributions (quantity, angle and energy distribution) along the top, walls and bottom of Fins or trenches based on simple geometrical model with shadowing effect.3-Calculation of local in depth dopant distribution on all points of the structure based on TRIM Monte-Carlo simulation4-Recalculation of mean concentration profile and comparison with 1.5D SIMS.Effect of main process parameters (plasma density and pressure) is shown as well as geometrical parameters of doped structures (aspect ratio, tapering angle). After having compared the model to experimental data, impact of geometrical changes due to technology scaling is discussed (fin pitch for Finfet application, form factor for trench doping applications)