Reduction of n-type diamond contact resistance by graphite electrode

The contact resistance between heavily phosphorus doped n-type (n(+)-type) diamond (111) layers and graphite electrodes was investigated. To analyze the contact resistance properties in detail in the low-voltage region, the transfer length method including nonlinear terms with a constant current was analyzed based on the double Schottky contact configuration. Using this method, we have revaluated the metal contact resistance reported previously. Using the graphite electrodes, the linearity of current-voltage characteristics was improved. The contact resistance was reduced by a factor of ten compared to that of conventional Ti/Pt/Au electrodes. The graphite electrodes were formed directly by thermal annealing at 1300 degrees C for 10 min from an n(+)-type diamond surface. ((c) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)