Effects of Plasma Treatment on the Electrical Properties of AlGaN/GaN Schottky Diodes with Graphene/Ni/Au Electrodes

Abstract

We investigated the structural and electrical characteristics of graphene after O-2 plasma treatment and H-2 annealing, and we further studied the effects of these treatments on the device performance of AlGaN/GaN Schottky diodes. Raman spectroscopy revealed that increasing O-2 plasma power during treatment enhanced the D-band to G-band intensity ratio. Atomic force microscopy and X-ray photoelectron spectroscopy revealed variation in surface morphology and a shift in carbon and oxygen binding energies, respectively, which correlated an increase in the sheet resistance of graphene. The current-voltage (I-V) characteristics of AlGaN/GaN Schottky diodes demonstrated degradation of electrical properties after O-2 plasma treatment. After H-2 annealing, the I-V curves of Schottky diodes recovered due to improvement in the structural and electrical properties of graphene damaged during O-2 plasma treatment.