Improvement of Laser-Crystallized Silicon Film Quality via Intermediate Dielectric Layers on a Glass Substrate

Abstract

The laser crystallization (LC) of amorphous silicon thin films into polycrystalline silicon (pc-Si) thin films on glass substrates is an active field of research in the fabrication of Si-based thin film transistors and thin film solar cells. Efforts have been, in particular, focused on the improvement of LC technique. Adhesion promoters of the crystallized Si thin films at the glass interface play a crucial role in the stability and device performance of fabricated structures. The crystalline Si thin films are required to be produced free of contamination risks arising from impurity diffusion from the glass substrate. Moreover, it is preferable to fabricate pc-Si thin films at temperatures as close as possible to the ambient temperature for an effective cost reduction. In this work, we demonstrate the successful use of a commercially available nanosecond pulsed laser marker at 1064 nm wavelength for Si crystallization at ambient conditions compared to the common method of pre-elevated substrate temperatures used in continuous wave laser irradiation technique. As a result, our technique results in a better energy balance than that in previous works. The second main purpose of this study is to enhance the crystallinity of Si thin films and to determine the best choice of an intermediate dielectric layer (IDL) comparatively among four thin buffer layers, namely, SiN x , SiO 2 , ZnO, and TiO 2 , for the sake of obtaining improved adhesion and larger crystalline domains as compared to that on a direct Si–glass interface. The crystalline qualities of samples containing IDLs of SiN x , SiO 2 , ZnO, and TiO 2 were compared via Raman spectroscopy analysis and electron backscatter diffraction method against the direct Si–glass interface reference. The analyses quantitatively showed that both the crystallinity and the domain sizes can be increased via IDLs.

Enhancement of the Silicon Solar Cell Efficiency by Spin-Coated Polythiophene Films Embedded with Gold or Palladium Nanoparticles on the Rear Contact

“…9 Intermediate dielectric layer (IDL) such as TiO 2 , for improving adhesion and obtaining larger crystalline silicon to enhance the direct Si−glass interface, was applied for thin-film silicon solar cells. 10 A conducting polymer was used to make polymer solar cells (PSC). 11 Polythiophene (PT) is a widely used donor material for solution-processed polymer solar cells.…”

“…Coating solar cells or panels with nanostructures have recently been extensively investigated to boost the efficiency of the cells . Intermediate dielectric layer (IDL) such as TiO 2 , for improving adhesion and obtaining larger crystalline silicon to enhance the direct Si–glass interface, was applied for thin-film silicon solar cells …”

A Dual-Wavelength Pulsed Laser Processing Platform for a-Si Thin Film Crystallization

“…The most important reason is high material cost. To that end, the thin film technology is one of prominent solutions for reducing fabrication cost of Si based devices [1][2][3]. Producing pc-Si thin films by means of in situ laser crystallization (LC) on various substrates draws attention in the electronic industry, especially for Si based TFTs and solar cell applications.…”

“…Producing pc-Si thin films by means of in situ laser crystallization (LC) on various substrates draws attention in the electronic industry, especially for Si based TFTs and solar cell applications. In situ LC process is an adequate and cost-effective method in order to decrease the fabrication costs of pc-Si thin films on various substrates [3].…”

“…Ytterbium doped nanosecond pulsed fibre laser operating at 1064 nm was used for crystallization of hydrogenated amorphous silicon (a-Si:H) thin film on glass [4]. A line-collimated optical fibre laser at 1064 nm was employed with a repetition rate of 80 kHz for crystallization process of de-hydrogenated a-Si thin film [3]. Moreover, a CW laser was used for liquid-phase crystallization (LPC) in other studies [4,6,7].…”