Solid-phase reactions of metal films deposited on 0.5-μm-thick polycrystalline layers of Si grown by chemical vapor deposition at 640 °C were investigated by MeV 4He backscattering spectrometry, glancing angle x-ray diffraction, and SEM observations. For the metals Al, Ag, and Au, which form simple eutectics, heat treatment at temperatures below the eutectic results in erosion of the poly-Si layer and growth of Si crystallites in the metal film. Crystallite formation is observed at T≳550 °C for Ag, T ≳400 °C for Al, and T ≳200 °C for Au films. For the metals Pd, Ni, and Cr, heat treatment results in silicide formation. The same initial silicides (Pd2Si, Ni2Si, and CrSi2), are formed at similar temperatures on single-crystal substrates.
The behavior of Ti−Mo−Au metallization on Al2O3 and C has been investigated by backscattering spectrometry. Results show that Mo−Au bimetal films typically mix during deposition. Diffusion of Ti in Mo film occurs at 600°C, but is inhibited by the presence of oxygen in the Ti film. Even 1000 Å of Mo is not a barrier against interdiffusion of Ti and Au during 20−min anneals at 600°C. The amount of mixing observed also depends on the nature of the substrate which supports the Ti−Mo−Au metallization.
Articles you may be interested inGaN epitaxial films grown by hydride vapor phase epitaxy on polycrystalline chemical vapor deposition diamond substrates using surface nanostructuring with TiN or anodic Al oxideThe influence of titanium nanoparticles embedded in the surface of silicon substrates by ultrasonic agitation on diamond chemical vapor deposition was studied. The deposited diamond particle density ͑DPD͒ was found to be substantially enhanced by using a mixed slurry ͑Di/Ti͒ compared to abrasion with a diamond slurry solely. It was also determined that, under the ultrasonic agitation conditions used in this work, the addition of titanium particles to the abrasive suspension does not affect the quantity of embedded diamond growth centers, nor does it alter their chemical character. Rather, the Ti particle additives are active during the initial stages of deposition. Ion implantation experiments show that diamond homoepitaxially grows on diamond residues, and that Ti residues do not serve as nucleation centers. The annihilation of diamond growth centers prior to stable substrate formation is attributed to hydrogen etching, while the effect of thermal annealing is negligible. These experiments show that Ti residues do not prevent the etching of diamond debris. We therefore conclude that the increase in DPD is related to an enhancement in diamond growth that is induced by the Ti additives. We suggest that the enhanced growth is the result of Ti catalyzed surface reactions.
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