Field aided lateral crystallization of amorphous silicon with large grain formation

Field aided lateral crystallization of amorphous silicon has been carried out at 500 deg. C with an electric field of 200 V/cm. Scanning electron microscopy and optical microscopy show that large crystalline silicon grains with sizes over 100 μm have been formed in the laterally crystallized region. Raman spectroscopy shows that the large grain with size over 100 μm has a crystalline phase. The secondary ion mass spectrometry shows that the nickel concentration in the lateral diffused region is comparable to that of amorphous region beyond the nickel diffusion front. Nickel diffusion facilitated by the electric field and current flow has been found to be distinct in obtaining extremely large grains at a low temperature of 500 deg. C. This enhanced lateral crystallization process is capable of producing large polycrystalline silicon grains, which is desirable for fabrication of thin film transistors used in large area electronics