Modelling of flash-lamp-induced crystallization of amorphous silicon thin films on glass

Smith, M.; McMahon, R.A.; Voelskow, M.; Panknin, D.; Skorupa, W.

doi:10.1016/j.jcrysgro.2005.08.033

Cited by 69 publications

(61 citation statements)

References 17 publications

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“…The spectral distribution of this light mainly covers the visible and near infrared range, and only a minor part extends to the near ultraviolet range. 36 Consequently, direct interactions between the light radiation and gas molecules, i.e. photolytic effects, are negligible, and the FLA treatment only leads to a short term heating of the illuminated surface.…”

Section: Principle Of Flash-enhanced Aldmentioning

confidence: 99%

“…The spectral distribution of the emitted light covers mainly the visible range with maximum intensities at wavelengths of about 470 and 570 nm. 36 The relationship between the provided electrical energy and the light energy at the substrate surface has not been determined so far. For this reason, all values concerning the flash energy density refer to the applied electrical energy, and thus, specify the upper limit in case of an energy conversion factor of 1 when illuminating a 100 mm wafer.…”

Section: Process Toolmentioning

confidence: 99%

“…[34][35][36][37][38] Consequently, FLA is a suitable technology to power high temperature processes even on temperature sensitive substrates. 34 Examples for the application of FLA are the activation of dopants and the defect annealing after ion implantation to form ultra-shallow junctions, 37,38 the crystallization of amorphous silicon in order to produce crystalline silicon on various substrates, 36,[39][40][41] the thermal treatment of high-k dielectrics for memory and transistor applications 42,43 and of transparent conductive oxide films for solar cell applications, 34 the sintering of particles 44 as well as ink-jet printed films, 45 and the deposition of thin films. [22][23][24][25][26][27][28][29] The latter use of FLA is the object of flash-enhanced ALD, which we describe in the following also abbreviated as FEALD.…”

mentioning

confidence: 99%

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Flash-Enhanced Atomic Layer Deposition: Basics, Opportunities, Review, and Principal Studies on the Flash-Enhanced Growth of Thin Films

Henke

Knaut

Hoßbach

et al. 2015

ECS J. Solid State Sci. Technol.

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Within this work, flash lamp annealing (FLA) is utilized to thermally enhance the film growth in atomic layer deposition (ALD). First, the basic principles of this flash-enhanced ALD (FEALD) are presented in detail, the technology is reviewed and classified. Thereafter, results of our studies on the FEALD of aluminum-based and ruthenium thin films are presented. These depositions were realized by periodically flashing on a substrate during the precursor exposure. In both cases, the film growth is induced by the flash heating and the processes exhibit typical ALD characteristics such as layer-by-layer growth and growth rates smaller than one Å/cycle. The obtained relations between process parameters and film growth parameters are discussed with the main focus on the impact of the FLA-caused temperature profile on the film growth. Similar, substrate-dependent growth rates are attributed to the different optical characteristics of the applied substrates. Regarding the ruthenium deposition, a single-source process was realized. It was also successfully applied to significantly enhance the nucleation behavior in order to overcome substrate-inhibited film growth. Besides, this work addresses technical challenges for the practical realization of this film deposition method and demonstrates the potential of this technology to extend the capabilities of thermal ALD. Atomic layer deposition (ALD) is a specific thin film deposition method wherein film growth is based on a sequence of alternating saturated surface reactions. In a typical ALD process, this is realized by the alternating exposure of the substrate surface to two precursors, which are separated from each other by inert gas purging or chamber evacuation in order to prevent gas phase reactions. As a result, the film growth proceeds in a self-limiting manner and monolayer-by-monolayer, and thus, ALD enables the deposition of thin films with excellent uniformity and conformality as well as with sub-nanometer thickness control. Thanks to these unique characteristics, ALD has emerged as an important thin film deposition technique in semiconductor technology, e.g. in the fabrication of metal-insulator-metal (MIM) film stacks in high aspect ratio dynamic random access memory (DRAM) structures and gate dielectrics in transistors. In recent years, the use of ALD has also expanded into other fields such as optoelectronics, energy conversion and storage devices, micro-electro-mechanical-systems (MEMS) and nanotechnology. [1][2][3][4][5][6] Although a large number of materials have been deposited by ALD so far 1-6 for various applications, there are still a number of challenges in ALD. The deposition temperatures in ALD are mostly lower compared to chemical vapor deposition (CVD) processes due to the different mechanisms of film growth and the necessity to prevent precursor decomposition in order to keep the self-limiting growth behavior of ALD. As a consequence of the lower energy available for film formation, the films may not meet the properties required for the specific...

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Section: Principle Of Flash-enhanced Aldmentioning

confidence: 99%

Section: Process Toolmentioning

confidence: 99%

mentioning

confidence: 99%

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Flash-Enhanced Atomic Layer Deposition: Basics, Opportunities, Review, and Principal Studies on the Flash-Enhanced Growth of Thin Films

Henke

Knaut

Hoßbach

et al. 2015

ECS J. Solid State Sci. Technol.

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“…However, the formation of surface projections and stretched grains cannot be explained by the simple ESPN, and the melting of the large-grain regions must be considered. During the lateral crystallization process, a-Si regions close to the heat-emitting poly-Si receive more heat than relatively distant a-Si regions, and can be heated up to its melting point of 1145 °C [15], resulting in the partial melting of a-Si. The neighboring a-Si may not completely melt because of its large latent heat of fusion of a-Si (35.4 kJ/mol) [15].…”

Section: Discussionmentioning

confidence: 99%

“…During the lateral crystallization process, a-Si regions close to the heat-emitting poly-Si receive more heat than relatively distant a-Si regions, and can be heated up to its melting point of 1145 °C [15], resulting in the partial melting of a-Si. The neighboring a-Si may not completely melt because of its large latent heat of fusion of a-Si (35.4 kJ/mol) [15]. The stretched grains probably result from liquid-phase epitaxy to solid-phase-nucleated small grains.…”

Section: Discussionmentioning

confidence: 99%

Polycrystalline Si films with unique microstructures formed from amorphous Si films by non‐thermal equilibrium flash lamp annealing

Ohdaira

Nishikawa

Shiba

et al. 2010

Phys. Status Solidi (c)

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Flash lamp annealing (FLA), with millisecond‐order duration, can crystallize amorphous silicon (a‐Si) films a few μm thick on glass substrates, resulting in formation of polycrystalline Si (poly‐Si) films with unprecedented periodic microstructures. The characteristic microstructure, formed spontaneously during crystallization, consists of large‐grain regions, containing relatively large grains more than 100 nm in size, and fine‐grain regions, including only 10‐nm‐sized fine grains. The microstructures results from explosive crystallization (EC), driven by heat generation corresponding to the difference of the enthalpies of meta‐stable a‐Si and stable crystalline Si (c‐Si) states, which realizes lateral crystallization velocity on the order of m/s. The lateral crystallization may stop when the temperature of a‐Si in the vicinity of c‐Si, which is decided by both homogeneous heating from flash irradiation and thermal diffusion from c‐Si, falls below a crystallization temperature. This idea is supported by the experimental fact that a lateral crystallization length decreases with decreasing pulse duration. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Thin Film Polycrystalline Silicon Solar Cells

Beaucarne

Slaoui

2006

Thin Film Solar Cells

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We have fabricated thin-film solar cells using polycrystalline silicon (poly-Si) films formed by flash lamp annealing (FLA) of 4.5-µm-thick amorphous Si (a-Si) films deposited on Cr-coated glass substrates.High-pressure water-vapor annealing (HPWVA) is effective to improve the minority carrier lifetime of poly-Si films up to 10 µs long. Diode and solar cell characteristics can be seen only in the solar cells formed using poly-Si films after HPWVA, indicating the need for defect termination. The actual solar cell operation demonstrated indicates feasibility of using poly-Si films formed through FLA on glass substrates as a thin-film solar cell material.

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Modelling of flash-lamp-induced crystallization of amorphous silicon thin films on glass

Cited by 69 publications

References 17 publications

Flash-Enhanced Atomic Layer Deposition: Basics, Opportunities, Review, and Principal Studies on the Flash-Enhanced Growth of Thin Films

Flash-Enhanced Atomic Layer Deposition: Basics, Opportunities, Review, and Principal Studies on the Flash-Enhanced Growth of Thin Films

Polycrystalline Si films with unique microstructures formed from amorphous Si films by non‐thermal equilibrium flash lamp annealing

Thin Film Polycrystalline Silicon Solar Cells

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