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A device is described to facilitate direct comparative measurements of vapor pressures with multiple effusion cells attached to a mass spectrometer, particularly for the reproducibility of mechanical repositioning of the cells and the ionization conditions of the molecular beam in the ion source. Measurements show that with this device this method can be applied satisfactorily to the determination of thermodynamic activities in high-temperature systems.

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ABSTRAC'I'Precise structural analysis of Mo/Si multilayers deposited by a diode il-sputtering system has been made using in -situ ki netic ellipsoinetry, grazing X -ray reflection , X-ray di firact ion , Auger profile analysis , R utherford hackscattering and high resolution electron microscopy. The main structural imperfections (interface roughness and interdiffusion ), have been related to the Mo crystallization and to the molybdenum suicide formation at the interfaces. The comparison to (7o/Si muitilayers deposited in the same conditions was useful to deduce the influence of the intrinsic properties of these systems on their structural behavior. Silicide layers arc formed in real-time during the growth of the samples. lhcir are completely amorphous and their composition is not far from defined compounds ( MoSi2 and CoSI2 ). Iii iWü/Si multilayers the 1\1() on Si interface is always thicker than the other interface ( 1 5 A compared to 8 A . It is not due to the deposition conditions hut to the crystallization of the molybdenum layers which reduces the SIlicon diffusion at the Si on l\to interface. 'the higher reactivity of cobalt with silicon produces thicker quasisymetric silici(lc layers ( 25 A ). The thermal behavior of the two systems is also controlled by the interdiffusion and the crystallization of the suicide layers. Absolute soft X-ray reflection was measured on different 1o/Si X-ray mirrors by synchrotron radiation at various wavelengths aboVe thC Si I -line, and related to the structural characteristics. In spite of the occurance of thin silicide layers at each intcthicc, reflectivitics as high as 55% in normal mcideuce have been obtained at I 30 A I .INTRODtJ( liON Mo/Si inultilayer niirrors with high reflectivitics have hcen fabricated in nany laboratories. Indeed, due to a very high index contrast above the Si I-line, maxinium reflectivity values above 5tV can be expected for the wavelength region between I 2 A and 25() A . So, a lot of cfh'rts have been concentrated Ofl this material pair for various applications such as astronomical telescopes' 2, X-ray laser caity mirrors, or X-ray microscopy4.A great nunber of deposition methods have been t.ised: inagnctron sputtering, electron beam deposition6 , ion -hcain sputtenngR, (IC and if sput tcring. If c xcellcnt mirrors have been obtained by different deposition methods, O-8194-0675-9/92/$4.Qo SPIE Vol. 1547 Muftilayer Optics for Advanced X-Ray Applications(1991) / 21 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/15/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx