RAMAN-SCATTERING INVESTIGATION OF CN IN ANNEALED CON CN SOFT-X-RAY MULTILAYERS/

The Roman features of CN layers in annealed CoN/CN soft-x-ray multilay ers, deposited by dual-facing-target sputtering, are investigated. The Roman spectra resemble that of amorphous carbon. The features that ar e different from those of Co/C multilayers (Bai H L, Jiang E Y and Wan g C D 1996 J. Appl. Phys. 80 1428) include: (1) the integral intensity ratio I(D)/I(G) of the D line to the G line increases with the anneal ing temperature, but the peak feature observed at 600 degrees C in the I(D)/I(G) versus temperature curve of the Co/C multilayers no longer exists; (2) in the temperature range of the annealing, the D-line posi tion changes from 1352.1 to 1367.7 cm(-1), and the G-line position fro m 1553.7 to 1594.0 cm(-1); the D- and G-line positions for as-deposite d M4-CoN/CN multilayers are much higher than those of Co/C multilayers , and close to those for polycrystalline graphite; (3) the linewidths of the D and G lines decrease with the increasing annealing temperatur e, and they are much lower than those for Co/C multilayers. These resu lts indicate that the primary bonding in the CN sublayers is sp(2). In other words, the formation of the sp(3) bonding in the CN sublayers c an be suppressed effectively by doping with N atoms, and thus the peri od expansion resulting from the changes in the density of the CN layer s can be decreased considerably. With tie low-angle x-ray diffraction measurements, we do observe a great decrease in period expansion.