Pressure-induced polymorphic transformation in single-crystal Si

Pressure-induced phase transformations in lightly and heavily B-doped Si wafers subjected to nanoindentation tests have been studied using Raman microspectroscopy. The effects of load levels and loading/unloading rates on the phase transformations were systematically investigated, and resultant phase transformation maps were plotted. For heavily B-doped Si, the regions in which the resulted phases are amorphous Si, and amorphous Si mixed with Si-Ⅲ and Si-Ⅻ enlarge to a wider range, suggesting that heavy B doping promotes the amorphization of Si. Preliminary analysis of phase transformation kinetics indicates that the polymorphic transformation may not be accomplished by long-range or short-range diffusion, instead, just via interfacial atom rearrangement.