Low energy ion-assisted deposition of titanium nitride ohmic contacts on alpha (6H)-silicon carbide

Low energy (100 eV) ion-assisted reactive evaporation was used to deposit titanium nitride (TiN) onto single crystal α(6H)-silicon carbide (SiC) wafers to investigate the potential of the former for electrical contacts. Theoretical considerations indicate that TiN (work function of 3.74 eV) should form an ohmic contact with SiC [work function of 4.8 eV for the (0001) face] provided an oxide-free interface can be obtained. Activated nitrogen was used to clean the SiC surface prior to deposition, while Auger spectroscopy and current-voltage (I-V) measurements were used to assess oxygen concentration at the interface and contact character, respectively. The contacts were ohmic after deposition. Little change was observed after annealing at 450 and 550 °C for 15 min.