Dependence of thermal annealing on the density distribution of interface states in Ti/n-GaAs(Te) Schottky diodes

The Ti/n-GaAs(Te) Schottky barrier diodes have been annealed in the temperature range 200-400 degrees C with steps of 100 degrees C for 5 min. The barrier height value has increased with increasing annealing temperature. This increase has been attributed to that the annealing removes the passivation effect of the native oxide layer and reactivates the surface defects which are responsible for the Fermi level pinning. The value of equilibrium interface charge density Q(ss)(0) has increased with increasing annealing temperature. It has been found that the experimental density distribution curves of the interface states and the values of equilibrium interface charge density Q(ss)(0) has confirmed this interpretation. The results indicate that the negative equilibrium interface charge is responsible for the actual equilibrium barrier height value. (C) 1999 Elsevier Science B.V. All rights reserved.