Excimer laser crystallization of amorphous silicon on metallic substrate

• Published in: Applied physics. A, Materials science & processing Vol. 111; no. 3; pp. 807 - 812
• Main Authors: Delachat, F., Antoni, F., Slaoui, A., Cayron, C., Ducros, C., Lerat, J.-F., Emeraud, T., Negru, R., Huet, K., Reydet, P.-L.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.06.2013; Springer
• Subjects: Amorphous silicon; Biological and medical applications; Characterization and Evaluation of Materials; Condensed Matter Physics; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystallization; Energy density; Exact sciences and technology; Excimer lasers; Fundamental areas of phenomenology (including applications); Industrial applications; Machines; Manufacturing; Materials science; Methods of nanofabrication; Nanoscale pattern formation; Nanostructure; Nanotechnology; Optical and Electronic Materials; Optics; Physical radiation effects, radiation damage; Physics; Physics and Astronomy; Processes; Scanning electron microscopy; Silicon films; Structure of solids and liquids; crystallography; Surfaces and Interfaces; Thin Films; Ultraviolet, visible, and infrared radiation effects (including laser radiation); Amorphous Silicon; Pulse Excimer Laser; Metallic Foil; Thin Film Solar Cell; Laser Fluence; Amorphous semiconductors; Digital simulation; Crystallization; Laser assisted processing; Nanostructures; Laser beam applications; Thin films; Surface melting; Cathode sputtering; Impurities; Laser beam annealing; Nickel; Silicon; Radiofrequency sputtering
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-013-7643-1

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.