Effect of interfacial mixing by N+ implantation on the adhesion and friction of Ti film on Si3N4

Abstract

A thin ion-plated Ti film on sintered Si3N4 was implanted with 110 keV N+ at doses of 1 x 1016 to 3 x 1017 ions cm-2 and a substrate temperature of 60°C. The adhesion of the ion-plated Ti film and the N+-implanted films on Si3N4 was examined using a scratch tester and a scanning electron microscope. The interfacial chemistry of the N+-implanted Ti/Sl3N4 specimens was examined using sample tilting diffraction (STD), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). It was found that at a dose of 3 x 1017 N+ cm-2, the critical load for the scratch test on the N+-implanted Ti film/Si3N4 substrate increased from 10.8 to 50.0 N; consequently, the implanted films were not easily removed by interfacial failure as in the case of the unimplanted one. AES indicated that N+ implantation produced substantial interfacial mixing and interfacial grading in the Ti/Si3N4 system. The STD and XPS analyses revealed that a TixN (x = 1, 2) compound was formed by N+ implantation. The combination of these effects in the N+implanted Ti/Si3N4 specimen provided an increased adhesion that was approximately 4.6 times that of the unimplanted system. In addition, the hydrocarbon adsorbed in the near-surface region of Ti films reduced the adhesion component of friction between the metal and the N+-implanted specimen.