Electrical characteristics and interfacial reactions of rapidly annealed double metal Pd/Ti Schottky structure on n-type InP

We report on the effect of annealing temperature on electrical, interfacial reactions and surface morphological properties of Pd/Ti Schottky contacts to n-type InP. Measurements showed that the Schottky barrier height of as-deposited Pd/Ti Schottky contact is 0.58 eV (I-V) and 0.79 eV (C-V) respectively. It is observed that the barrier height increases to 0.67 eV (I-V) and 0.87 eV (C-V) for the contact annealed at 250 °C. Experimental results show that after annealing at temperature of 350 °C and 450 °C, the barrier heights decreases to 0.60 eV (I-V), 0.82 eV (C-V) and 0.54 eV (I-V), 0.73 eV (C-V) respectively. From the above observations, the optimum annealing temperature for the Pd/Ti Schottky contact is 250 °C. Based on the AES and XRD analysis, the formation of the indium phases at the Pd/Ti/n-InP interface could be the reason for the increase in the barrier height at annealing temperature 250 °C. Further, the degradation of the barrier heights after annealing at 350 °C and 450 °C may be due to the formation of phosphide phases at the Pd/Ti/n-InP interface. Atomic force microscopy (AFM) result shows that the overall surface morphology of the Pd/Ti Schottky contacts is reasonably smooth.