Aluminum induced formation of SiGe alloy in Ge/Si/Al thin film structure

In this work, a study of aluminum induced crystallization (AIC) of thin film germanium/silicon/aluminum (Ge/Si/Al) structure on oxidized silicon is presented. The Ge/Si/Al trilayer structure was prepared in three consecutive thin film deposition processes. The AIC was performed in nitrogen at 500 °C within time duration between 1 and 9 h. The progress of crystallization was monitored by optical microscopy, Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDS). It was found that in Ge/Si/Al structure the AIC can lead to formation of SiGe alloy at temperature of 500 °C. This presents an alternative low-temperature formation method of SiGe which is suitable for integration with the conventional Si technology in electronic device fabrication.

► Metal induced crystallization of amorphous Ge/Si layers was investigated in Ge/Si/Al/oxidized silicon structure.
► Above structure was compared with well established crystallization of a-Si in Si/Al oxidized silicon structure.
► The structures were annealed at 500 °C and crystallization was monitored.
► A formation of SiGe layer was recorded.
► A qualitative model was proposed for aluminum induced formation of SiGe alloy.