Identification of geometrically necessary dislocations in solid phase crystallized poly-Si

Abstract

In this work, the presence of geometrically necessary dislocations (GNDs) in polycrystalline silicon (poly-Si) thin films was detected, suggesting that plastic deformation occurs during the solid phase crystallization (SPC) process of amorphous silicon (a-Si:H). Electron backscatter diffraction was used to characterize dislocations in SPC poly-Si thin films. The elevated temperatures during SPC allow the GNDs to rearrange into arrays, forming low angle grain boundaries. We found that GNDs start forming in poly-Si grains with sizes >∼3 μm, suggesting that larger grains are more defective. GNDs are extra defects in addition to the existing statistically stored dislocations that form during grain growth and hence more care needs to be taken to minimize the formation of GNDs. © 2013 AIP Publishing LLC.