Solid-phase crystallization behaviors of in situ phosphorous-doped amorphous silicon films deposited using Si2H6 and PH3

Abstract

The solid-phase crystallization of in situ phosphorous-doped amorphous silicon films deposited by low-pressure chemical vapor deposition using disilane is studied for various P concentrations and annealing temperatures. The nucleation rate is found to follow a power law with respect to the annealing time. The power index is 1.3 for P concentrations up to about 5×1019 cm−3 and decreases slightly at higher P-doping levels. The grain growth rate is enhanced as the P concentration increases, particularly above 1×1019 cm−3. The activation energy of the grain growth rate is 2.6 eV regardless of the P concentration. The final grain size in the crystallized films increases markedly for a P concentration over 1×1019 cm−3, but is almost independent of the annealing temperature. The crystallization behavior and final grain size can be represented by equations extended from those of Avrami–Johnson–Mehl using the time-dependent nucleation rate.