Si0.8Ge0.2/Si(0.8)Geo(0.2)O(2) interface defects were studied by the e
lectron paramagnetic resonance (EPR) technique in 1 mu m thick epitaxi
al porous SiGe layers. Two different intrinsic interface defects, the
silicon and germanium P-b centers, have been identified. These defects
are respectively Si and Ge dangling bond centers with trigonal point
symmetry. The EPR parameters such as g-values, linewidths and spin con
centrations have been determined for different oxidation conditions: n
ative oxide formation at room temperature and 300 degrees C low-pressu
re oxidation. The spin concentrations of the two defects strongly depe
nd on the oxidation conditions. The spin concentration ratio differs f
rom the [Si]/[Ge] atomic concentration ratio of the porous layer.