Reduced pressure chemical vapour deposition of Si/Si1 x yGexCyheterostructures using a chlorinated chemistry

We have studied in reduced-pressure chemical vapour deposition the influence of the growth temperature on the interstitial–substitutional carbon incorporation ratio in SiGeC using dichlorosilane as the Si gas precursor. X-ray diffraction and secondary ion mass spectrometry were used in order to determine the substitutional and the total (interstitial + substitutional) carbon concentrations in the layers. Si/Si 1− y C y tensile-strained heterostructures were grown at 650 °C. The highest substitutional carbon concentration incorporated is around 0.75% (with a large amount of interstitial C atoms (also 0.75%), however). Low Ge concentration Si 1− x − y Ge x C y layers have also been grown. We have managed through the increase of the SiCH 6 mass flow to tailor the Si 1− x − y Ge x C y layer strain from compressive to tensile. The highest substitutional carbon concentrations obtained are 1.82% (0.95%) for growth temperatures of 600 °C (650 °C). Finally, compressively strained high Ge concentration Si 1− x − y Ge x C y layers with up to 3.20% (2.49% and 1.41%) in substitutional carbon atoms were grown at 550 °C (600 °C and 650 °C). The growth temperature does not seem to impact upon the total carbon concentration C T in these layers. Its dependence on the F (SiCH 6 )/( F (SiH 2 Cl 2 ) + F (GeH 4 )) mass flows ratio is indeed rather well fitted using the following relationship: C T 1.4 /(1 − C T ) = q( F (SiCH 6 )/( F (SiH 2 Cl 2 ) + F (GeH 4 )), with q in between 0.38 and 0.34 for the 550–650 °C temperature range. However, the more the temperature increases, the more the substitutional/interstitial carbon incorporation ratio is reduced.