The photoluminescence of strained Si1-xCx alloys, which had been grown at low temperatures by means of rapid thermal chemical vapor deposition, was investigated. The photoluminescence spectra were characterized mainly by a deep-level broad band, at low energy, which persisted up to room temperature. This low-energy emission was associated with the low-temperature growth that was required for the incorporation of C into substitutional sites. The stability of the layers after annealing was monitored by using the low-energy radiative recombination. A blue shift of the photoluminescence energy peak was observed, and the peak intensity exhibited a maximum as a function of annealing time. The blue shift and the associated increased line-width were explained in terms of local strain-induced band-gap fluctuations. The infra-red transmission spectra of the annealed samples suggested that SiC precipitates appeared during annealing, and that O and C complexes contributed to the formation of the deep-level band.

P.Boucaud, C.Francis, A.Larré, F.H.Julien, J.M.Lourtioz, D.Bouchier, S.Bodnar, J.L.Regolini: Applied Physics Letters, 1995, 66[1], 70-2