Laterally confined large-grained Poly-GeSi films: Crystallization and dopant activation using green laser

This paper reports crystallization with a pulsed Yb:YAG thin disk laser (λ = 515 nm) of amorphous Ge0.85Si0.15 films approximately 100 nm thick, on silicon wafers with thermal oxide. Pre-patterned lines were employed to steer the crystallization and to form confined large grains. In total, 64% of the grains were longer than 2 μm, among them 40% were reaching 8–35 μm in length. These values, orders of magnitude larger than the layer thickness, were a result of so-called super-lateral growth. The grains were laterally confined within a 3 μm wide space. The crystallization led to a substantial residual tensile stress with a strain of 3.4%. Green-laser activation of BF2 +, As+ and P+ implants was studied in amorphous and polycrystalline Ge0.85Si0.15 films and led to successful dopant activation with resistivity values in the range of 5–20 m_-cm achieved for all the implants.