Nanoindentation-induced phase transformations in silicon at elevated temperatures.

ABSTRACT

The nanoindentation-induced phase transformation behavior of silicon at elevated temperatures (25-150 degrees C) has been studied. Nucleation of Si-III/Si-XII on unloading is enhanced with increasing temperature and at the highest temperatures in an amorphous Si matrix, occurs in a continuous fashion without a pop-out event. Interestingly, for slow unloading at the highest temperatures, formation of Si-III/Si-XII in a crystalline Si matrix was not observed. Elevated temperatures enhance the nucleation of Si-III and Si-XII during unloading but the final composition of the phase transformed zone is also dependent on the thermal stability of the phases in their respective matrices.