The electrical assessment of Si1-xGex/Si heterostructures

A comprehensive electrical characterisation of the SiGe/Si heterostructures has been performed in the wide temperature range (10-270 K). For this study die structures fabricated by the ion implantation technique at three different substrate temperatures (room temperature, 150 C and 450 C) have been used. The presence and parameters of shallow and deep levels and the diode performance were studied as a function of the substrate temperature. The sample implanted at 450 C shows the best diode operation reflecting the higher quality of the surface silicon layer as compared to RT- and 150 C-implanted samples. For the first time the cryogenic TSCR technique has been applied to this system which makes it possible to investigate strain in the silicon layer due to SiGe layer formation.