LARGE-AREA POLYCRYSTALLINE SILICON THIN-FILMS GROWN BY LASER-INDUCED NUCLEATION AND SOLID-PHASE CRYSTALLIZATION

We present investigations on a two-step technique for the growth of po lycrystalline silicon thin films on glass substrates. In the first ste p, a lattice of artificial seeds is created by laser crystallization o f amorphous silicon. In the second step, crystallites are grown around the seed by thermal annealing below 600 degrees C. For seed separatio ns of 7 mu m, adjacent crystallites can coalesce before spontaneous nu cleation becomes apparent. Transmission electron microscopy reveals th at the crystallites are star shaped, consisting of domains separated b y twin boundaries. Microscopic reflection difference spectroscopy meas urements reveal the existence of a radial stress pattern around the se eds. We conjecture that this stress drives the lateral growth around t he seeds during thermal annealing.