Electric-field effect on metal induced crystallization of amorphous silicon

Anomalous crystallization behavior has been found for metal induced crystallization (MIC) of amorphous silicon (a-Si). The Ni density of ̃10¹³ atoms/cm² was deposited uniformly over whole a-Si layer and then the 2nd Ni layer was selectively deposited onto the a-Si using a shadow mask with Ni density of ̃10¹⁵ atoms/cm ². The crystallization started at first in the high Ni density (approx. 10¹⁵ atoms/cm²) region as a result of MIC in an electric field and then the a-Si in low Ni density (approx. 10¹³ atoms/cm²) region was laterally crystallized. However, the lateral crystallization proceeded in radial direction from the high Ni density region, forming disk-like grains, even though a parallel bias-field was applied. Then, the crystallization speed increased with the electric field strength. The lateral crystallization speed showed an exponential relationship with the electric field as r=r_oe^αE with constant r _o and α of 2.2×10^-2 cm/V. The dependence appears to be due to the reduction in the activation of Ni diffusion in an electric field.