Electrical properties of reactively sputtered CNx films

Carbon nitride (CNx) films have been deposited with an opposed-targct Penni ng-type sputtering source. The DC resistivity of films with different nitro gen content has been investigated using the four-point probe method and van der Pauw structures. The resistivity of nitrogen containing films is consi derably higher than nitrogen-free films. From temperature-dependent resisti vity measurements, the activation energy was found to increase with nitroge n content and from optical absorption measurements, the optical band,gap wa s calculated as 0.4 eV for pure carbon films and small gaps ( similar to 0. 1 eV) were found for nitrogen containing films. The resistivity and the ref ractive index of the films was found to correlate with the C=N bond density . (C) 1999 Elsevier Science S.A. All rights reserved.