Characterization of specific contact resistance on heavily phosphorus-doped diamond films

Specific contact resistance of Ti contact on phosphorus-doped diamond film has been characterized by means of circular type transfer length method. The resistance was significantly reduced down to ∼ 10− 3 Ω cm2 orders using heavily phosphorus-doped diamond film (n+) with phosphorus concentration over ∼ 1020 cm− 3, although an ideal ohmic property was not obtained. The results are explained by a narrowing of the Schottky barrier width of Ti/n+ interface for tunneling through the barrier to take place, indicating that the heavily doping is promising method for reducing the contact resistance for n-type diamond.