A study on the conduction path in undoped polycrystalline diamond films

The conduction path in as-grown undoped diamond films deposited by chemical vapor deposition has been investigated by employing impedance spectroscopy , electroplating and electroetching. The thickness- and direction-dependenc ies of electrical resistivity did not agree with the previously known surfa ce conduction model. The Cu electroplating and Ag electroetching results sh owed that the current path followed the grain boundaries within the diamond films. The Cu electroplating of diamond film with an insulating surface la yer also showed that the grain boundaries within the films were the main co nduction path in undoped polycrystalline films. (C) 2001 Elsevier Science B .V. All rights reserved.