Interface study of a Co/Si/W/Si multilayer with enhanced thermal stability

• Published in: Journal of applied crystallography Vol. 33; no. 3-1; pp. 753 - 757
• Main Authors: Jergel, M., Anopchenko, A., Holý, V., Majková, E., Luby, Š., Senderák, R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England Munksgaard International Publishers 01-06-2000; Blackwell
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Semiconductor materials; X-ray reflection; XRD; Amorphous state; Solid-solid interfaces; Experimental study; Cobalt; Metal-semiconductor contacts; Diffuse scattering; Thermal stability; Thin films; Multilayers; Rapid thermal annealing; Transition elements; Nonmetals; Tungsten; Silicon
• ISSN: 1600-5767; 0021-8898; 1600-5767
• DOI: 10.1107/S0021889800099842

The interface evolution in an amorphous Co/Si/W/Si multilayer (ML) of 150 Å nominal period processed by rapid thermal annealing (RTA) in the temperature range of 523‐1273 K for 5‐30 s was studied by X‐ray reflectivity and diffuse scattering measurements at Cu Kα1 wavelength. The results were simulated within the Fresnel theory and the distorted‐wave Born approximation. The interdiffusion and intermixing induced by RTA starts at Co/Si interfaces and takes place via an interface shift without a considerable increase of the interface roughness up to the 873K/30s RTA. A strong conformality of the interface profiles, stretching originally over the entire ML thickness in the whole interval of the interface roughness frequencies covered by the experimental scans, is reduced to about 2 ML periods. After the 1023K/30s RTA, the interface morphology is controlled by the crystallization of Co and W silicide phases leading to interface roughening. The vertical interface correlation is sensititve to the interface roughness frequency. A fast diffusion along grain boundaries leads to a complete interdiffusion and collapse of the ML on 1273K/30s RTA. Compared with a W/Si ML studied previously, the incorporation of Co layers into the ML stack enhanced the thermal stability by about 250 K. Some consequences for optical applications are discussed.