Single-crystal Si films for thin-film transistor devices

Abstract

The fact that single-crystal Si would make an ideal material for thin-film transistor devices has long been recognized. Despite this awareness, a viable method by which such a material could be directly produced on a glass substrate has never been formulated. In this letter, it is shown experimentally that location-controlled single-crystal Si regions on a SiO2 surface can be obtained in a glass-substrate compatible manner, via excimer-laser-based sequential lateral solidification of thin Si films using a beamlet shape that self-selects and extends a single grain over an arbitrarily large area. This is accomplished by controlling the locations, shape, and extent of melting induced by the incident excimer-laser pulses, in such a manner as to induce interface-contour-affected sequential super-lateral growth of crystals, during which the tendency of grain boundaries to align approximately orthogonal to the solidifying interface is systematically exploited.

Oriented Lateral Growth and Defects in Polycrystalline-Silicon Thin Films on Glass Substrates

“…Flow-shaped growth of Si films has been achieved via techniques such as sequential-lateral solidification (SLS), selectively enlarging laser crystallization (SELAX), and CW laser lateral crystallization (CLC) (Im et al, 1997;Crowder et al, 2000;Hatano et al, 2002;Hara et al, 2002b;Fujii et al, 2007). SLS and SELAX employ pulsed excimer lasers and pulse-modulated diode-pumped solid-state (DPSS) CW lasers (a Nd:YVO 4 laser with a wavelength of 532 nm), respectively, as heat sources.…”

A reliable approach to a rapid calculation of the grain size of polycrystalline thin films after excimer laser crystallization

“…Excimer laser crystallization (ELC) is an industrial technique used for preparing poly-Si thin films on commercially available, inexpensive glass substrates for the development of high-performance TFTs in active-matrix flat panel displays. [1][2][3][4][5][6] A rapid deposition of the laser-energy density, on a nanosecond time scale, onto the surface region of the an amorphous-silicon (a-Si) thin film leads to its melting and recrystallisation into a poly-Si thin film, while keeping the glass substrate at a low temperature. The final quality of the device depends significantly on the phase-transformation mechanisms which need to be manipulated precisely for obtaining poly-Si thin films with a large grain size and a good uniformity.…”

Polycrystalline silicon films prepared by metal-induced crystallisation using pre- and post-deposited aluminium on amorphous silicon

“…Alternative processes have been proposed, including laser annealing and metal-induced crystallisation (MIC). Laser annealing is a fast process but suffers from poor spatial uniformity and a narrow processing window [1]. Various metal-induced crystallisation methods have been proposed to shorten the annealing time and lower the processing temperature.…”