Study on thermal emission of charges at Si3N4-GaAs interfaces after annealing in N2 and N2 + H2 mixtures

Si3N4-GaAs interfaces subjected to annealing in N2 + H2 mixture or pure N2 atmosphere were investigated by a small-signal charge deep-level transient spectroscopy (Q-DLTS) method. The method measures the physical parameters of selective populations of the interface traps continuum. A dependence of the capture cross-section on activation energy was constructed for the continuum of interface states at the Si3N4-GaAs interface. The dependence shows an exponential character in the part of the gap ranging from 0.3 to 1.0 eV below the conduction band minimum. It was found that annealing in the temperature interval 400-450°C reduces the zero-bias band bending by about 0.1 eV. At temperatures of 500°C and more, degradation of the interface started; compared with annealing in pure N2 ambient, annealing in an N2 + H2 mixture degraded the interface slightly more.