Effects of annealing temperature on electrical and structural properties of Mo/n-InP (100) Schottky contacts

The electrical, structural and surface morphological properties of Mo/n-InP Schottky diodes have been investigated as a function of annealing temperature using current-voltage (I-V), capacitance-voltage (C-V), Secondary Ion Mass Spectroscopy (SIMS), X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements. The obtained Schottky barrier heights from I-V and C-V measurements for as-deposited Mo/n-InP are 0.45 eV and 0.61 eV respectively. Upon annealing at 300 degrees C in nitrogen atmosphere for 1 min, the barrier height values increased to 0.47 eV (I-V) and 0.68 eV (C-V). When the samples are annealed at temperatures 400 and 500 degrees C, the barrier height values decrease to 0.46 eV (I-V), 0.44 eV (I-V) and 0.65 eV (C-V), 0.64 eV (C-V). The SIMS and XRD results showed the formation of phosphide phases at the Mo/n-InP interface, which may be the reason for the decrease in the barrier height for samples annealed at 500 degrees C. The AFM measurements showed that the surface morphology of Mo contacts on n-InP is smooth with a root mean square value of 12.7 nm even after annealing at 500 degrees C. Copyright (C) 2009 John Wiley & Sons, Ltd.