Electrical properties of Ti/SiC Schottky barrier diodes

Silicon carbide Schottky barrier diodes were fabricated with Ti Schottky contacts. The contacts were deposited at different temperatures ranging from 28 $^o$C to 900 $^o$C using a magnetron sputtering deposition system. The diodes were then annealed at 500 $^o$C in vacuum for up to 60 hours. Diodes with the contacts deposited at 200 $^o$C and annealed for 60 hours had the optimum current-voltage characteristics consisting of large barrier height of 1.13 eV and ideality factor of 1.04. These diodes also had a very low leakage current of 6.6 x 10-$^8$ A at a reverse voltage bias of 400 V. The X-ray diffraction analysis of the Ti/SiC contacts revealed the formation of TiC, Ti5Si3 and Ti3SiC2 at the interface. The improved properties for diodes with contacts deposited at 200 $^o$C could be related to formation of reaction products possessing high work functions. These improvements could provide significant gains in performance of 4H-SiC Schottky diodes where Ti is a common metal contact.