Effect of thermal annealing on the electrical and structural properties of Au/Y/p-type InP Schottky structure

The effects of rapid thermal annealing on the electrical and structural properties of a fabricated Au/Y/p-InP Schottky barrier diode (SBD) have been investigated. The estimated Schottky barrier heights (SBHs) of the as-deposited and 200 °C annealed Au/Y/p-InP SBDs are found to be 0.62 eV (I-V)/0.83 eV (C-V) and 0.63 eV (I-V)/0.92 eV (C-V) respectively. However, the SBH increases to 0.65 eV (I-V)/0.96 eV (C-V) upon annealing at 300 °C. Further, the SBH slightly decreases to 0.59 eV (I-V)/0.78 eV (C-V) for contact annealed at 400 °C. The SBH, ideality factor and series resistance of the Au/Y/p-InP SBD are estimated by Norde and Cheung's methods. Also, the discrepancy between SBHs estimated from I-V, C-V, Norde and Cheung's methods are described and discussed. It is noted that the interface state density of the Au/Y/p-InP SBD decreases upon annealing at 300 °C and then slightly increases after annealing at 400 °C. The AES and XRD measurements have revealed that the formation of Au-In, Au-P and Y-P interfacial phases at the interface may be the reason for the increase and decrease of SBHs upon annealing. The AFM results showed that the surface morphology of the Au/Y Schottky contact is fairly smooth at various annealing temperatures.