Ohmic contact formation mechanism of Ni on n-type 4H–SiC was proposed by comparing the electrical properties with microstructural change. The ohmic behavior was observed at temperatures higher than 900C, but Ni2Si phase, as formerly reported to be responsible for ohmic contact, was formed after annealing at 600C. The higher work function of Ni2Si than Ni and the observation of graphite phase on the surface of Ni silicide after annealing at 950C support that a number of C vacancies were produced below the contact, playing a key role in forming an ohmic contact through the reduction of effective Schottky barrier height for the transport of electrons.

Ohmic Contact Formation Mechanism of Ni on n-Type 4H–SiC. S.Y.Han, K.H.Kim, J.K.Kim, H.W.Jang, K.H.Lee, N.K.Kim, E.D.Kim, J.L.Lee: Applied Physics Letters, 2001, 79[12], 1816-8