Process Simulation of Pulsed Laser Annealing on Epitaxial Ge on Si

Abstract

Using a 3D numerical method, temperatures of pulsed laser annealed epi-Ge layers on SOI and bulk Si substrates are simulated. Epi-Ge is phosphorus-doped by in-situ chemical vapor deposition doping. Both the simulated melt depth and the measured sheet electron density of epi-Ge increases as the laser fluence increases. A strong positive correlation is observed between the simulated melt depth of epi-Ge and the measured sheet electron density. The sheet electron density is calculated using the temperature-dependent solid solubility, while the electron concentration for epi-Ge melted during pulsed laser annealing is assumed to be the liquid solubility of phosphorus at melting point. An intermixing between Ge and Si is observed by cross-sectional transmission electron microscopy, when both Si and epi-Ge are melted in the simulation.