PHOTOLUMINESCENCE CHARACTERIZATION OF SI1-XGEX RELAXED PSEUDO-SUBSTRATES GROWN ON SI

Photoluminescence of high-quality relaxed Si1-xGex pseudo-substrates g rown by rapid thermal chemical vapour deposition, consisting of Si1-xG ex relaxed capping layers with a 0.32 or 0.52 Ge content and a composi tionally graded Si1-xGex buffer layer, is reported. The composition gr adient has been shown to play a determinant role in the layer quality. The PL spectra show well-resolved band edge photoluminescence issued from the relaxed alloy capping layer and defect-related bands associat ed with dislocations in the graded buffer layer. The detailed analysis of the dislocation bands demonstrates that the main misfit dislocatio ns remain confined in the graded buffer layer. Well-defined PL results obtained on Si1-xGex layers grown in compressive and tensile strain o n these pseudo-substrates are discussed on the basis of strain symmetr ization and of the high quality of the layers. The possibility to use such high-quality relaxed Si1-xGex layers as substrates for integratio n of new devices associated with Si technology is pointed out.