Data for Microstructural evolution of mechanically deformed polycrystalline silicon for kerfless photovoltaics

Here we report a study using mainly high resolution electron backscatter diffraction (HR-EBSD) of the microstructural evolution of Siemens polycrystalline silicon feedstock during a series of processes designed to mimic high temperature rolling. The starting material is heavily textured and annealing at 1400 ˚C results in 90% recrystallization and a reduction in average geometrically necessary dislocation (GND) density from >1014 m-2 to 1013 m-2.

Subsequent compression at 1150 ˚C – analogous to rolling – produces subgrain boundaries seen as continuous curved high GND content linear features spanning grain interiors. Post-deformation annealing at 1400 ˚C facilitates a secondary recrystallization process, resulting in large grains typically of 100 µm diameter. HR-EBSD gives the final average GND density in as 3.2  1012 m-2 .