We have studied in reduced pressure-chemical vapor deposition, the low-temperature growth kinetics of high Ge content Si1-xGex and high C content Si1-yCy layers on Si(001). The Ge concentration x dependence on the F(GeH4)/ F(SiH2Cl2) mass flow ratio is well accounted for at 550 degrees C by x(2)/(1-x) = 2.66F(GeH4)/F(SiH2Cl2). The associated SiGe growth rate linearly increases as the F(GeH4)/F(H-2) mass flow ratio increases, from 0.15 nm min(-1) (23% Ge) up to 3.9 nm min(-1) (47% Ge). We have then quantified the macroscopic loading effects (i.e. the strong growth rate increase) that occur when switching from bulk, blanket to patterned, ultra-thin silicon-on-insulator (SOI) wafers. The Si1-xGex layers grown at 550 degrees C inside Si windows or on blanket wafers remain flat even for very high Ge contents (47%). Finally, through an important increase of the silane and methysilane partial pressures, we were able to obtain at 550 degrees C good quality, 15nm thick Si1-yCy layers with substitutional C concentrations as high as 2.1%, with almost no interstitial C atoms (0.1% only). The dependence of the substitutional and of the total (i.e. substitutional + interstitial) C concentrations y on the F(SiCH6)/F(SiH4) mass flow ratio at 550 degrees C can satisfactorily be fitted using y/(1-y) = in (F(SiCH6)/F(SiH4)) relationships, with m(subst.) = 0.64 and m(total) = 0.78. (c) 2005 Elsevier B.V. All rights reserved.