Excimer laser crystallization of amorphous silicon on metallic substrate
An attempt has been made to achieve the crystallization of silicon thin film on metallic foils by long pulse duration excimer laser processing. Amorphous silicon thin films (100 nm) were deposited by radiofrequency magnetron sputtering on a commercial metallic alloy (N42-FeNi made of 41 % of Ni) coated by a tantalum nitride (TaN) layer. The TaN coating acts as a barrier layer, preventing the diffusion of metallic impurities in the silicon thin film during the laser annealing. An energy density threshold of 0.3 J cm-2, necessary for surface melting and crystallization of the amorphous silicon, was predicted by a numerical simulation of laser-induced phase transitions and witnessed by Raman analysis. Beyond this fluence, the melt depth increases with the intensification of energy density. A complete crystallization of the layer is achieved for an energy density of 0.9 J cm-2. Scanning electron microscopy unveils the nanostructuring of the silicon after laser irradiation, while cross-sectional transmission electron microscopy reveals the crystallites' columnar growth. © 2013 Springer-Verlag Berlin Heidelberg.
Keywords: Amorphous silicon ; Amorphous silicon thin films ; Cross sectional transmission electron microscopy ; Diffusion coatings ; Energy density threshold ; Excimer laser crystallization ; Excimer laser processing ; Excimer lasers ; Laser induced phase transitions ; Long pulse durations ; Radio frequency magnetron sputtering ; scanning electron microscopy ; Silicon ; Tantalum compounds ; Thin films ; Transmission electron microscopy
Record created on 2014-11-14, modified on 2016-08-09