Polycrystalline silicon thin films for microelectronic applications

Polycrystalline silicon thin films with a thickness of 0.5-2μm were grown on 25nm thick Ni prelayers by d.c. magnetron sputtering from a Si target. In contrast to the conventional sputtering, the use of a thin Ni film allows the production of high crystallinity silicon at a temperature of 475°C and higher. The Ni disilicide grains formed at the Ni-growing Si film interface provide sufficient sites for the epitaxial growth of Si. The Si films with resistivity of 10²-10³Ω-cm possess a carrier lifetime of up to 11μs and a diffusion length of up to 3.4 μm, which makes them applicable to various microelectronic devices. As an example, Schottky diodes fabricated on 0.5μm thick Si films exhibit a forward-to-reverse current ratio of 10⁷. The technique is easily implemented on a variety of substrates.