Electron levels and luminescence of dislocation networks formed by the hydrophilic bonding of silicon wafers

Local energy levels produced by dislocations at the interface between bonded n - and p -Si wafers are studied by deep level transient spectroscopy and by a new technique for the detection of impurity luminescence, induced by the occupation of electron states upon the application of electric pulses (the pulsed trap-refilling-enhanced luminescence technique). It is established that only the shallow levels of the dislocation network, with activation energies of about 0.1 eV, are responsible for the D 1 dislocation-related luminescence band in both n - and p -type samples. The occupation of deep levels has no effect on the D 1-band intensity. A model of coupled neutral trapping centers for charge carriers is proposed. In this model, the difference between the energy position of the D 1 band (0.8 eV) and the corresponding interlevel energy spacing (0.97 eV) is attributed to the Coulomb interaction between charge carriers trapped at the levels.