Numerical analysis of forward I–V characteristics of Au/InP interface restructured by antimony

In this paper, the numerical analysis of the electrical quality of an Au/InP structure processed by antimony is investigated. We have developed a simulation program of the I–V characteristic that takes into consideration the effect of the InSb layer as well as the surface states. The obtained results show that Au/InP contacts with many surface states (NTS=3×1013 cm−3) present a resistive contact for a doping concentration smaller than 5×1016 cm−3. For larger doping concentration, the contact is a rectifier, and the diffusion potential is important (>0.65 V). Restructuring of the Au/InP (Nd=5×1016 cm−3) interface with a InSb layer of thickness in the range of 6–10 Å, allows on the one hand, to obtain a good Schottky contact (rectifying contact) where the direct current is important and on the other hand, to decrease the diffusion potential to 0.45 V. If the layer thickness is larger than 20 Å, the direct current decreases, and the contact becomes resistive. By simulating the effect of the surface states density, we have confirmed that they have less influence on the electrical characteristic. This result confirms consequently that the electrical quality depends more on the nature of the material to be used for the restructuring. A good agreement with experimental results has been obtained for Au/InP structures unrestructured and restructured by antimony.