Electrical And Structural Properties of (Pd/Au) Schottky contact to As Grown And Rapid Thermally Annealed Gal\ Grown by MBE

We studied effect of thermally annealed GaN surface on the electrical and structural properties of (Pd/Au) Schottky contact to Ga-polar GaN grown by molecular beam epitaxy on Si substrate. Current voltage (I-V) measurement was used to study electrical properties while X-ray diffraction (XRD) measurement was used to study structural properties. The Schottky barrier height calculated using 1-V characteristics was 0.59 eV for (Pd/Au) Schottky contact on as grown GaN, which increased to 0.73 eV for the Schottky contact fabricated on 700 degrees C annettled GaN film. The reverse bias leakage current at -1 V was also significantly reduced from 6,42 x 10(-5) A to 7.31 x 10(-7) A after annealing. The value of series resistance (R-s) was extracted from Cheung method and the value of R-s decreased from 373 Omega to 172 Omega after annealing. XRD results revealed the formation of gallide phases at the interface of (Pd/Au) and GaN for annealed sample, which could be the reason for improvement in the electrical properties of Schottky contact after annealing.