Grain boundaries in p-n junction diodes fabricated in laser-recrystallized silicon thin films

Grain boundaries intersecting metallurgical p-n junctions have been evaluated in laser-recrystallized silicon thin films. Lateral p-n junction diodes were fabricated in islands of polycrystalline silicon which were defined on an amorphous substrate and cw laser recrystallized. The oxide-passivated diodes display good current rectification. Correlated scanning electron microscopy (electron-beam induced current and voltage contrast) and transmission electron microscopy reveal that the electrical junction strongly deviates from the linear boundary between the n and p regions defined by ion implantation. Spikes in the junction profile arise from enhanced dopant diffusion along grain boundaries.