Divacancy-related complexes in Si (1− x )Ge ( x )

• Published in: Materials science in semiconductor processing 2006-08, Vol.9 (4), p.525-530
• Main Authors: Khirunenko, L.I., Pomozov, Yu.V., Sosnin, M.G., Trypachko, M.O., Duvanskii, A.V., Abrosimov, N.V., Riemann, H., Lastovskii, S.B., Murin, L.I., Markevich, V.P., Peaker, A.R.
• Format: Article
• Language: English
• Subjects: Alloys; Applied sciences; Electron paramagnetic resonance (EPR); Electronics; Exact sciences and technology; Materials
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2006.08.030

In the present work, V 2-related defects have been studied in SiGe alloys by means of infrared (IR) absorption spectroscopy, electron paramagnetic resonance (EPR) and deep-level transient spectroscopy (DLTS). The defects have been induced by electron irradiations at 80 K and subsequent isochronal anneals. In oxygen-lean SiGe samples after annealing out of Ge–V centers in the temperature range of 250–300 K an absorption band with maximum at about 5680 cm −1 has been found. An appearance of a new EPR signal Si-UA1 has been registered simultaneously. It is found from an analysis of the angular dependences of the EPR spectrum that the corresponding center has monoclinic-I symmetry with the principal values of g tensor: g 1=2.0154, g 2=2.0084 and g 3=2.0039. It is argued that the absorption line and the EPR signal are related to Ge–V 2 complex. The formation of Ge–V 2 centers has also occurred upon heat treatments of SiGe samples in the temperature range of 400–450 K. It is associated with the capture of mobile divacancies by Ge atoms. The disappearance of the Ge–V 2 center upon heat treatments at T>480 K is found to result in a shift of the absorption band to lower frequencies and in a shift of a DLTS peak associated with the Ge–V 2(+/0) transition to higher temperatures. It is suggested that these shifts are related to a conversion of Ge–V 2 centers into Ge 2–V 2 complexes.