CATHODOLUMINESCENCE AND EBIC STUDY ON MISFIT DISLOCATIONS IN SIGE SI HETEROSTRUCTURE/

Optical and electrical activities of misfit dislocations in SiGe/Si fi lms were studied by means of cathodoluminescence (CL) and electron bea m induced current (EBIC) technique. The dominant type of dislocations were densely spaced dislocations and isolated dislocations running alo ng the two [110] directions identified by X-ray topographs. Strong D2, D3 and D4 luminescence was observed from the densely spaced dislocati ons, while weak D1 luminescence was observed at some regions where dis locations intersect each other. The intensity distribution of D2 lumin escence is nonuniform along misfit dislocations compared with that of D3. No D-line luminescence was observed from isolated dislocations. Bo th densely spaced dislocations and isolated dislocations are EBIC acti ve below 200 K, indicating that they are free from serious metallic co ntamination. The ratio of radiative recombination to total recombinati on at a region of densely spaced dislocations is less than 1%, which s uggests that the energy state of dislocation spreads in the momentum s pace.