Mechanism of field-aided lateral crystallization of amorphous silicon

The crystallization mechanism of the amorphous silicon using the field-aided lateral crystallization process was studied. The crystallization initiates at the negatively biased side and progresses towards the positively biased side with an enhanced velocity. In addition, the crystallization velocity increases monotonically as the applied voltage increases to a point, and then decreases beyond the critical voltage point. The current level measurement during the heat treatment of simple test patterns showed that the resistivity of the Ni-free amorphous silicon was reduced by 4 orders of magnitude at 510 degrees C. The current density under the bias of 100 V is in the range of 100 A/cm(2), which is enough to cause the electromigration at that temperature. Using the Nernst-Einstein equation, we prove that the process is governed by competition between the field-assisted diffusion and electromigration. (c) 2005 American Institute of Physics.