Electrical characterization of 4H–SiC Schottky diodes with a RuO2 and a RuWO x Schottky contacts

Abstract

Two types of Schottky diodes were prepared on n-type silicon carbide (4H–SiC) substrates by deposition of ruthenium oxide (RuO2) Schottky contacts or ruthenium tungsten oxide (RuWO x ) Schottky contacts. The RuO2/4H–SiC and RuWO x /4H–SiC Schottky barrier diodes were examined first by current–voltage (I-V) measurements, which confirmed symmetry of the I-V characteristics. The ideality factor (n) is rather high (∼1.28/∼1.15) at the temperature 300 K, the current of saturation is I S ∼10 pA/∼7 pA and the Schottky barrier height is ∼1.13 eV/∼1.11 eV. After this diagnostic step, the samples were analysed by C-V and standard DLTS methods in the temperature range from 83 K to 450 K. In measured DLTS spectra were identified five deep levels ET1–ET5 (0.27, 0.45, 0.56, 0.58 and 0.85 eV) in RuO2/4H–SiC Schottky barrier diodes and three deep levels E1–E3 (0.36, 0.38 and 0.69 eV) in RuWO x /4H–SiC Schottky barrier diodes.