Novel method for the formation of large-grained, silicon thin films on amorphous substrates

We describe a novel, solid-phase crystallization method for synthesizing large-grained, textured silicon films on amorphous substrates at relatively low processing temperatures (≤550°C). This method is based on the use of a roughened single-crystal silicon seed which is pressed onto the amorphous silicon surface. The composite structure is then annealed at low temperatures (<550°C) for times ranging from 2 to 10 h in a furnace so that crystallization from the surface layers is achieved. X-ray diffraction measurements showed that the films processed by the surface-seeded crystallization (SSC) method exhibited a (110) texture. Transmission electron microscopy revealed the presence of very large [110] grains (>10 μm) for films crystallized by the SSC method Hall measurements conducted on boron-doped films, annealed at 800°C, showed excellent hole mobility with values exceeding 180 cm²/Vs, which was almost a factor of six higher than that found in porycrystalline films obtained from standard annealing procedures (annealing temperature ∼600°C for 28 h).