Impurity-induced enhancement of the growth rate of amorphized silicon during solid-phase epitaxy: A free-carrier effect

The study of solid-phase epitaxy in ion-implanted amorphized silicon is presented via optical reflectivity measurements. The effect of impurities on recrystallization is studied in detail through accurate measurements of growth rate. Enhancement of the growth rate and decrease of the activation energy are shown. These parameters are studied as a function of the impurity concentration. This phenomenon is understood in terms of an original model which introduces band bending and an electric field at the disordered layer-crystalline substrate interface. The electric field acts on recrystallization through the enhancement of defect migration at the interface. The agreement of the model with experimental results is shown to be excellent, and a parallel is drawn with the phenomenon of enhanced dislocation mobility with doping, which behaves in a strikingly similar way.