Green laser recrystallization of poly-SiGe thin films deposited by RPCVD system

Laser recrystallization of the polycrystalline silicon germanium (poly-SiGe) thin films was studied using a pulsed green laser. The poly-SiGe films were directly grown by the RPCVD system, and annealed using an optimized scan configuration and at various laser fluence. The properties of these annealed films were characterized in detail. It was shown that, under a proper fluence (about 0.5 mJ per pulse), the number of grain boundaries is extensively reduced and the grain size approximately triples. As a consequence, the sheet resistance of the annealed film is more than 2 orders of magnitude smaller than that of the as-grown film. The roughness of the annealed surface is also improved, with the root-mean-square value being reduced from 11.54 to 4.75 nm.