PREPARATION AND STRUCTURAL STABILITY INVESTIGATION OF CON CN SOFT-X-RAY MULTILAYERS/

The structural stability of heat-treated CoN/CN soft X-ray multilayers fabricated by dual-facing-target sputtering has been investigated by using complementary measurement techniques. The high temperature annea ling results imply that the destructive threshold of the Co/C multilay ers is improved by 100-200 degrees centigrade through doping with N. T he low-angle X-ray diffraction of CoN/CN soft X-ray multilayers indica tes that the period expansion of the multilayers is only 4% at 400 deg rees C, and the interface pattern still exists even if they were annea led at 700 degrees C. The Raman spectra analyses give the evidence tha t the formation of the sp(3) bonding in the CN sublayers can be suppre ssed effectively by doping N with atoms, and thus the period expansion resulting from the changes in the density of CN layers can be decreas ed considerably. The X-ray photoelectron spectra analyses present the information of the existence of the strong covalent bonding between C and N atoms, and the ionic bonding between Co and N atoms, which tan s low down the tendency of the structural relaxation. The interstitial N atoms decrease the mobility of Co atoms, and thus the ice-Co and hcp- Co coexist even though the annealing temperature is much higher than t he phase transformation temperature of 420 degrees C, leading to the s uppression of the grain growth.