COMPARISON OFTHE Ti/n-GaAs SCHOTTKY CONTACTS' PARAMETERS FABRICATED USING DC MAGNETRON SPUTTERING AND THERMAL EVAPORATION

Abstract

We have fabricated the Ti/n-type GaAs Schottky diodes (SDs) by the DC magnetron deposition and thermal evaporation, cut from the same GaAs substrates, and we have made a comparative study of the current-voltage (I-V) measurements of both SDs in the measurement temperature range of 160-300K with steps of 10 K. The barrier height (BH) values of about 0.82 and 0.76 eV at 300K have been obtained for the sputtered and evaporated SDs, respectively. It has been seen that the apparent BH value for the diodes has decreased with decreasing temperature obeying the single-Gaussian distribution (GD) for the evaporated diode and the double-GD for the sputtered diode over the whole measurement temperature range. The increment in BH and observed discrepancies in the sputtered diode have been attributed to the reduction in the native oxide layer present on the substrate surface by the high energy of the sputtered atoms and to sputtering-induced defects present in the near-surface region. We conclude that the thermal evaporation technique yields better quality Schottky contacts for use in electronic devices compared to the DC magnetron deposition technique.