Monte Carlo Simulation of Coupled Ion-Electron Transport in Semiconductors

The Monte Carlo ion-transport code TRIPOS is extended to a new version, TRIPOS-E, for modeling secondary-electron generation and transport along ion tracks. Energy deposition and radial electron-hole (e-h) pair profiles in silicon are evaluated for several energetic heavy ions. These profiles reflect a Gaussian-like central core which decreases exponentially at increasing radial distance. Analytical expressions for radial charge-density profiles at several depths of penetration are obtained. The excess charge density remains above background dopant concentrations beyond 0.25 μm radius from the ion path. This detailed evaluation of track structure should enhance modeling of charge collection from ion tracks in semiconductor devices.