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 (less than or equal to 550 degrees 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 degrees 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 mu m) for films crystallized by the SSC method. Hall measurements conducted on boron-doped films, annealed at 800 degrees C showed excellent hole mobility with values exceeding 180 cm(2)/V s, which was almost a factor of six higher than that found in polycrystalline films obtained from standard annealing procedures (annealing temperature similar to 600 degrees C for 28 h).