In situ observation of low temperature growth of crystalline silicon using reflection high-energy electron diffraction

In situ observations of reflection high-energy electron diffraction (RHEED) have been performed to investigate the microcrystalline silicon formation mechanism in plasma-enhanced-chemical-vapor-deposition (PECVD) using a mixture of SiH4 and H2 at a temperature Ts between 27°C and 560°C. In low temperature epitaxy (LTE) on Si(0 0 1), we found that the epitaxial structure of films as a function of temperature had, at 120°C, a surface structure Si1 × 1 and at 430°C Si2 × 1, depending on hydrogen dilution. This bistable epitaxy is mediated by the surface hydrogen mode. In polycrystalline silicon growth on a ZnO coated glass substrate, we observed in situ the change in the order and disorder of the structure and the change in the orientation during the growth. These results can be utilized to control crystal growth by a real-time feed-back to deposition parameters. Thus, we have demonstrated that in situ reflection high-energy electron diffraction observation is useful for the study of microcrystalline silicon growth.