CHARACTERIZATION OF SI SI1-XGEX/SI HETEROSTRUCTURES BY CAPACITANCE-TRANSIENT SPECTROSCOPY/

Deep level distributions have been investigated in B-doped Si/Si1-xGex /Si layers grown by molecular beam epitaxy using deep level transient spectroscopy. Broadening in the deep level spectra is discussed in ter ms of carrier emission over a band of deep level energies as has been considered for both alloy disorder and dislocations. The distortion ob served in the deep level spectra in the vicinity of the upper Si/Si1-x Gex heterojunction is suggested to be a consequence of the significant band bending that occurs in this region; the possible causes for this distortion are discussed. The deep states exhibit donor-like behavior and the origin of the electrical activity is considered to lie with m etal point-defect/dislocation interactions.