Ion-beam induced modifications of titanium Schottky barrier on 4H-SiC

The effects of ion irradiation on the Ti/4H-SiC Schottky barrier are discussed. The Ti/SiC interfacial region of test Schottky diodes was irradiated with 8 MeV Si4+ ions at fluences between 1 x 10(9) and 1 x 10(12) ions/cm(2). By increasing ion fluence, an increase of the Schottky barrier &UPhi;(B) was observed, from &UPhi;(B) = 1.05 eV in the non-irradiated sample to &UPhi;(B) =1.21 eV after irradiation at the highest fluence, accompanied by a decrease of the leakage current. Using different experimental analytical techniques enabled us to correlate the modification of the interfacial region with the contacts electrical behaviour. In particular, the structural and electrical modifications in the near-interface region (different orientation of the Ti film, defects in the epilayer, dopant deactivation) were responsible for the change of the Ti barrier after irradiation.