Growth temperature dependence of substitutional carbon incorporation in SiGeC/Si heterostructures

Abstract

We have studied in reduced-pressure chemical vapor deposition the influence of the growth temperature on the interstitial-substitutional carbon incorporation ratio in SiGeC. Si1−yCy as well as high- and low-Ge concentration Si1−x−yGexCy layers were grown at 550, 600, and 650 °C. X-ray diffraction (XRD) and secondary ion mass spectrometry (SIMS) were used in order to determine the substitutional and the total (interstitial+substitutional) carbon concentrations. As far as high-Ge concentration Si1−x−yGexCy layers are concerned, compressively strained layers with up to 1.74% (1.26% and 0.62%) in substitutional carbon atoms were grown at 550 °C (600 and 650 °C). Low-Ge concentration Si1−x−yGexCy layers have also been grown. We have managed through the increase of the SiCH6 mass flow to tailor the Si1−x−yGexCy layer strain from compressive to tensile. The highest substitutional carbon concentrations obtained are 1.51% (1.21% and 0.92%) for growth temperatures of 550 °C (600 and 650 °C). Si1−yCy/Si tensile-strained heterostructures were also grown. The highest substitutional carbon concentration incorporated is around 1.44% (1.12% and 0.83%) at 550 °C (600 and 650 °C). Varying the Si1−x−yGexCy and Si1−yCy layers growth temperature does not seem to impact upon the total carbon incorporation. However, by comparing SIMS and XRD data, we showed that the more the temperature increases, the more the substitutional/interstitial carbon incorporation ratio is reduced.