The Stress-Dependence of Phase Changes in Silicon Under Indentation

This paper investigates the stress effect on the phase transformation events in silicon under varying indentation loads, cycles and environment. It was found that the combination of hydrostatic and deviatoric stresses in indentation plays an important role. With a single indentation cycle, the deformed zone can be amorphous, a mixture of crystalline and amorphous, or purely crystalline, depending on the level of the maximum indentation load. Under cyclic indentations, some phases can be initiated from the second indentation cycle and stabilized in the subsequent cycles. Water has an obvious effect on the indentation deformation, with which silicon becomes less ductile. Different shapes of indenter tips leads to dissimilar phase transformation processes.