Thermal behaviour of CorSirWrSi multilayers under high intensity excimer laser pulses

The thermal stability of e-beam deposited multilayers MLs.for soft X-ray reflection optics was studied under XeCl laser processing in vacuum. MLs with five CorSirWrSi periods, each 13.5 nm MLS1.or 18.4 nm MLS2.were deposited onto oxidized Si and irradiated at the fluences of 0.075–0.62 J cmy2 by 1 or 100 pulses. The samples were analyzed by X-ray diffraction, hard X-ray reflectivity and sheet resistance measurements. The layered structure of our samples persists up to 0.62 J cmy2 per 1 pulse for MLS2 and 0.62 J cmy2 per 100 pulses for MLS1 irradiations. The thermal stability of MLS1 is even better than for WrSi MLs studied previously. In laser irradiated samples the Co2Si3 phase which is normally formed under high pressures )4 GPa.was found. It has not been reported in the film couples so far. The high thermal stability and Co2Si3 formation in MLS1 are explained by complex Co–Si silicide formation conditions and compressive stress parallel to the surface of irradiated samples. q1999 Elsevier Science B.V. All rights reserved.