INVESTIGATIONS OF THE INDENTATION-INDUCED CRYSTALLOGRAPHIC PHASE CHANGES IN SILICON USING RAMAN SPECTROSCOPY

Raman spectroscopy, which is a non-destructive technique, has been used to investigate the effect of sample temperature on indentation-induced crystallographic phase transitions in crystalline silicon and amorphous silicon films deposited on a sapphire crystal. It has been shown that in both types of sample, whereas 300 K Vickers diamond indentations lead to the transformation to the Si-II phase during indenter loading on the crystalline and amorphous samples, there is no such transformation in either sample when it is cooled down to 77 K. An explanation of the experimental results has been provided using the pressure–temperature phase diagram of silicon.