Recent insights in solid phase epitaxy of silicon and germanium

The crystallization of amorphous layers via solid phase epitaxy (SPE) is commonly used in semiconductor device fabrication to activate dopants. The kinetics of SPE depend on temperature, dopant and impurity concentration, hydrostatic pressure and crystallographic orientation. The effect of H on SPE in both Si and Ge is discussed. Numerical simulations are performed to model the H diffusion, the moving amorphous/crystalline interfaces and the refinement of the II profile at these interfaces. Despite the high H concentration involved, a simple Fickian diffusion model results in good agreement with the SIMS data. A significant fraction of the H escapes from the a-Si layer during SPE and becomes trapped at end of range defects. The light-emitting properties of these defects are investigated. Finally, the formation of germanides via SPE is discussed.