In-situ P doped epitaxial Si(1-x)C(x) growth under UHV-CVD
Abstract:
Undoped and in-situ phosphorus-doped epitaxial Si(1-x)C(x) layers were grown on chemically cleaned Si (100) substrates by using a UHV-CVD process. The carbon concentrations of the epitaxial layers and growth temperatures were varied, and the effects of post annealing processes were then investigated. In the defect-free films, the carbon content in the Si(1-x)C(x) layer was analyzed to be about 1.2% by XRD measurement. About 20% loss of the substitutional carbon atoms occurred after annealing treatment at 1000 degrees C in N2 ambient due to the transfer of the substititual carbon atoms to interstitial sites as well as the formation of the β-SiC precipitates. The changes in microstructures were analyzed by the cross sectional transmission electron microscopy. The surface of the films shows partially polycrystalline structures in high PH, flow rate, due to surface poisoning by phosphorus segregation. Fully a 100% substitutionality of carbon atoms in the epitaxial Si(1-x)C(x) film is achieved by the addition of PH3 and post annealing.
