Ion-beam and laser mixing of nickel overlayers on silicon carbide

We have investigated ion-beam and laser mixing of Ni overlayers on silicon carbide substrates using cross-section and analytical techniques of electron microscopy, and ion scattering and channeling techniques. The thickness of the overlayers was varied from 200 to 500 A on both crystalline and polycrystalline substrates of silicon carbide. The thickness of the ion-beam mixed region was found to increase with increasing dose of the implanted ions. The laser mixing was obtained only within a critical window of the pulse energy density (1.15 +- 1.25 J cm-2) of a ruby laser (wavelength 0.693 μm, and pulse duration 28 x 10-9 s). The structure of the mixed region was found to be amorphous, with occasional presence of crystalline nickel silicide (Ni2Si) islands. The laser-mixed SiC specimens showed a considerable improvement (>35%) in their fracture strength