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

Improved Al/InP Schottky barriers are formed on n-InP by using coimpla ntation of Be/P. The doped surface layer (Be) helps in retarding the s urface fields, resulting in larger Schottky barrier heights. The addit ion of phosphorus prevents excessive P loss and enhances the percentag e of Be activation. A Schottky barrier height as high as 0.64 eV has b een 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 fo ur orders of magnitude. To demonstrate the versatility of our process, the same technique is applied to p-InP samples. As expected, the barr ier height is reduced by almost 0.5 eV. Furthermore, the sum of the tw o Schottky barrier heights also matches closely with the theoretical v alue of energy band gap for InP.