| Sequential lateral solidification (SLS) is a pulsed excimer-laser crystallization process that is compatible with high-temperature intolerant substrates and that permits flexible control of grain boundary placement during iterative lateral crystal growth of thin Si films; this capability can be used to produce low-defect-density crystalline Si films with precisely engineered microstructures.; A variety of intragrain planar defects are identified and characterized within the SLS-processed amorphous Si films, with sub-grain boundaries being the major intragrain defect (microtwin rich sub-grains are also found to be prevalent within the SLS-processed films). Such defects can only degrade the performance of microelectronic devices fabricated using the SLS-processed films. Single-crystal silicon-on-insulator (SOI) films are further utilized as the seed material for lateral epitaxial growth in order to systematically investigate the mechanisms that lead to the generation of these defects. The primary focus is on examining the generation of sub-grain boundaries that result from SLS processing, although it is found that the mechanisms that lead to the formation of sub-grain boundaries are also similar, if not identical, to those that lead to the formation of microtwin-rich regions. Implications of these results are discussed in relation to a plastic deformation model that is proposed to relate the formation of sub-grain boundaries in SLS-processed Si films to thermally-induced stresses that are present during the process. |
