Low temperature processing of a large grain polycrystalline silicon thin film on soda-lime glass

• Published in: Semiconductor science and technology 2011-09, Vol.26 (9), p.95031-6
• Main Authors: Wang, Kai, Wong, Kin Hung
• Format: Article
• Language: English
• Subjects: Aluminum; Carrier density; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystallization; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; Grains; Low-field transport and mobility; piezoresistance; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Physics; Semiconductors; Silicon; Silicon films; Soda-lime glass; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films
• ISSN: 0268-1242; 1361-6641
• DOI: 10.1088/0268-1242/26/9/095031

We have demonstrated that a polycrystalline silicon thin film can be fabricated in situ on soda-lime glass at 450 [degrees]C by an Al-induced crystallization method using electron beam evaporation. The catalytic Al is found to diffuse to the top of the crystallized Si layer and can be easily etched away by a mixture of acids. This low temperature Si crystallization process is well explained by thermodynamic consideration. Subsequent annealing at the same temperature (450 [degrees]C) for 6 h improves the crystallinity of the film and enlarges the average grain size to over 5 mu m. There are no observable impurity phases. The poly-Si thin films are (1 1 1) oriented and all the grains are well aligned. A defect-free and excellent crystalline structure has been revealed by transmission electron microscopy. The measured resistivity, carrier concentration and charge mobility of these as-prepared poly-Si thin films indicate that our present low temperature processing technique has great advantage and prospect for the photonics industry.