A study was made of the damage which was produced by the room-temperature implantation of high-quality 3-thick relaxed Si1-xGex alloys (x = 0.04, 0.13, 0.24 or 0.36) with 2MeV Si+ ions to a dose of between 1010 and 2 x 1015/cm2. The accumulation of damage with increasing dose was investigated by using Rutherford back-scattering spectrometric, optical reflectivity depth profiling, and transmission electron microscopic techniques. An increased level of damage, and a marked decrease in the critical dose for the formation of a buried amorphous layer, was observed with increasing x-value. Electron paramagnetic resonance studies showed that the main defects which were produced by implantation were Si and Ge dangling bonds in amorphous-like zones. The main effect of increasing the ion dose was to increase the volume fraction of the material that was present in this form, until a continuous amorphous layer formed. Comparison of the damage in various alloys revealed an appreciable increase in the primary production of amorphous nuclei in alloys with an x-value of more than 0.04.

A.N.Larsen, C.O’Raifeartaigh, R.C.Barklie, B.Holm, F.Priolo, G.Franzo, G.Lulli, M.Bianconi, R.Nipoti, J.K.N.Lindner, A.Mesli, J.J.Grob, F.Cristiano, P.L.F.Hemment: Journal of Applied Physics, 1997, 81[5], 2208-18