Fabrication of 4H-SiC schottky barrier diodes with high breakdown voltages

This paper discusses the fabrication and the breakdown characteristics of 4H-SiC Schottky barrier diodes (SBDs). Optimal processing conditions for the ohmic contacts were extracted using the transmission-line method (TLM) and were applied to the device fabrication. The Ti/4H-SiC SBDs with Si _xN _y passivation showed a maximum reverse breakdown voltage of 268 V with a forward current density as high as 70 mA/cm ² at a forward voltage of 2 V. The breakdown of the Pt/4H-SiC SBDs without any passivation occurred at near 110 V. It is concluded that the breakdown enhancement in the Ti/4H-SiC SBDs can be attributed to the passivation; otherwise, excess surface charge near the edge of the Schottky contact would lead to electric fields of sufficient magnitude to cause field emission.