On the enhancement of effective barrier height in Ti/n-GaAs Schottky barrier diodes

Changes in the Current-Voltage (I-V) and Current-Voltage-Temperature (I-V-T) characteristics of Schottky Barrier Diodes (SBDs) on silicon doped n-GaAs (Titanium/n-GaAs) after irradiation using protons at 100 keV with various doses (5x10(13) to 1X10(15) cm(-2)) are presented and analysed. Irradiated SBDs reverse leakage current is more compared to the unirradiated SBDs. Heavily irradiated (1X10(15) cm(-2)) SBDs almost behaves like an Ohmic contact at 360 K. The irradiated SBDs were annealed at two different temperatures (200 and 350 degrees C for 15 min.) under nitrogen atmosphere and characterised using I-V and I-V-T measurements. Rectifying behaviour of the irradiated SBDs improves as the annealing temperature increases. Enhancement of the effective barrier height (Phi(e)) and improvement in the ideality factor (n) has been observed in annealed (350 degrees C for 15 min) proton irradiated Ti/n-GaAs SBDs. This may be either due to hydrogen passivation of GaAs surface and/or removal of hydrogen related irradiation induced defects in SBDs. On the unirradiated and annealed (upto 350 degrees C) there is no significant change in the characteristics as compared to the CONTROL SBDs.