IMPROVED AL/INP SCHOTTKY BARRIERS BY COIMPLANTATION OF BE/P

Improved Al/InP Schottky barriers are formed on n-InP by using coimplantation of Be/P. The doped surface layer (Be) helps in retarding the surface fields, resulting in larger Schottky barrier heights. The addition of phosphorus prevents excessive P loss and enhances the percentage of Be activation. A Schottky barrier height as high as 0.64 eV has been obtained, as compared to 0.55 eV for diodes without P implantation. The ideality factor is found to be very close to unity (almost-equal-to 1.08). The reverse leakage current density is reduced by almost four orders of magnitude. To demonstrate the versatility of our process, the same technique is applied to p-InP samples. As expected, the barrier height is reduced by almost 0.5 eV. Furthermore, the sum of the two Schottky barrier heights also matches closely with the theoretical value of energy band gap for InP.