Electrical characterization of 4H-SiC Schottky diodes with a RuO_2 and a RuWO_x Schottky contacts

摘要

Two types of Schottky diodes were prepared on n-type silicon carbide (4H-SiC) substrates by deposition of ruthenium oxide (RuO_2) Schottky contacts or ruthenium tungsten oxide (RuWO_x) Schottky contacts. The RuO_2/4H-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 RuO_2/4H-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.