Thin films of pure Cu, and Cu with 0.02 or 2.98wt%Ti were deposited onto SiO2-covered Si substrates. The samples were annealed at 500 to 800C in vacuum in order to investigate their morphological evolution, interfacial reaction and diffusion. X-ray diffraction revealed Cu(111) and Cu(200) peaks for pure Cu and Cu (0.02wt%Ti) films. However, the Cu (2.98wt%Ti) film exhibited a very weak Cu(200) peak, indicating that this film was textured in the <111> orientation. Concurrently, scanning electron microscopy showed that the grain size of the Cu(2.98wt%Ti) film was significantly smaller than those of pure Cu and Cu (0.02wt%Ti) films. In addition, Cu (2.98wt%Ti) film remained smooth after annealing at up to 800C, while the other 2 films became discontinuous. X-ray photo-electron spectroscopy indicated that a TiOx layer had formed at the Cu(0.02wt%Ti)/SiO2 and Cu(2.98wt%Ti)/SiO2 interfaces after 700C annealing. Nevertheless, the TiOx layer was thicker in the Cu (2.98wt%Ti) system than in the Cu (0.02wt%Ti) system. Consequently, the Cu (2.98wt%Ti) film showed no diffusion of Cu into SiO2 at up to 700C.

Effects of Ti Addition on the Morphology, Interfacial Reaction and Diffusion of Cu on SiO2. C.J.Liu, J.S.Jeng, J.S.Chen, Y.K.Lin: Journal of Vacuum Science & Technology B, 2002, 20[6], 2361-6