Low resistance Ti Ohmic contacts to 4H-SiC by reducing barrier heights without high temperature annealing

Ti Ohmic contacts to relatively highly doped (1 x 10(18) cm(-3)) n-type 4H-SiC have been produced, without high temperature annealing, by means of low temperature electronic cyclotron resonance microwave hydrogen plasma pre-treatment (HPT) of the SiC surface. The as-deposited Ti/4H-SiC contacts show Ohmic properties, and the specific contact resistance obtained is as low as 2.07 x 10(-4) Omega.cm(2) after annealing at low temperatures (400 degrees C). This is achieved by low barrier height at Ti/SiC interface, which could be attributed to decrease of surface states density by the HPT releasing Fermi level pinning, and to band-gap narrowing, image-force, and thermionic-field emission at high doping. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4730435]