Rapid thermal annealing effects on the electrical, structural and morphological properties of Yb/p-type InP Schottky Structure

The electrical, structural and surface morphological properties of Yb/p-InP Schottky barrier diode (SBD) have been investigated at different annealing temperatures. The determined Schottky barrier height (SBH) and ideality factor n of the as-deposited Yb/p-InP SBD are 0.68 eV (I-V)/0.81 eV((C-V)) and 1.44 respectively. After annealing at 300℃, the SBH of Yb/p-InP SBD increases to 0.72 eV (I-V)/0.88 eV ((C-V)). When the contact is annealed at 400℃, the SBH slightly decreases to 0.67 eV (I-V)/0.80 eV ((C-V)). These results reveal that the optimum annealing temperature for Yb/p-InP SBD is 300℃. Cheung’s functions are also employed to determine the series resistance of the Yb/p-InP SBD. Using Terman’s method, the interface state density is estimated for Yb/p-InP SBD at different annealing temperatures. The XPS results reveal that the existence of phosphorous-rich surface after the annealing. The AES and XRD results showed that the formation of phosphide phases at the Yb/p-InP interface may be the reason for the increase of SBH after annealing at 300℃. The decrease in the BH after annealing at 400℃ may be due to the formation of indium phases at the interface. The overall surface morphology of the Yb Schottky contact is fairly smooth at elevated temperatures.