Influence of the third harmonic pulsed Nd3+:YAG laser on the formation of a polycrystalline-silicon (poly-Si) on a-Si thin film with thickness of 1000 nm and 400nm in water and air ambience was investigated. In order to induce texturing of surface along with annealing, laser beam overlap technique with different percentages of spot overlap was used. Crystalline characteristics and electrical characteristics were studied to confirm the extent of crystallization. The crystalline characteristics of the film obtained with the Gaussian and the flat-top beam profiles were comparable for higher percentage of overlapping. Based on the theoretical modeling, the laser treatment without the ablation with the third output from the Nd3+:YAG laser was limited to the a-Si film thickness up to 800 nm. This was in qualitative agreement with the experimental observations. © 2016 The Authors

Nilesh Jayanthilal Vasa

Department of Engineering Design

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IIT Madras

Procedia Manufacturing

In the present research, an approach of converting amorphous-silicon (a-Si) thin films into polycrystalline thin films using the third harmonics of an all-solid-state pulsed Nd3+:YAG laser (355 nm) is studied. Two different samples of a-Si thin films on alkali-free glass (a-Si/glass) substrates and a-Si thin film on crystalline-Si substrates (a-Si/c-Si) are laser treated at different laser fluences ranging from 170 to 960 mJ/cm2. The amount of heat incident on the surface has been analyzed theoretically by solving the one-dimensional heat-equation model. The ablation threshold, the region of crystallization and the depth of crystallization have been investigated theoretically. The influence of laser irradiation, ablation and crystallinity has been experimentally analyzed through in-situ reflectivity measurements, scanning electron microscopy (SEM) and Raman spectroscopy studies. In the case of a-Si/c-Si, the extent of crystallinity and the influence of structural characteristics on electronic properties are studied using the Hall-effect technique. The ablation threshold and the range of crystallization regime are in good agreement with the theoretical results. Laser fluence between 300 and 500 mJ/cm2 is required for crystallization and the ablation threshold is estimated to be above 500 mJ/cm2 for a-Si thin film with a thickness up to 400 nm. © 2009 Elsevier Ltd. All rights reserved.

Materials Science in Semiconductor Processing

Crystallization and ablation in annealing of amorphous-Si thin film on glass and crystalline-Si substrates irradiated by third harmonics of Nd3+:YAG laser

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Enhancement in Photoconductivity of a-Si thin Films by Annealing and Texturing Technique with the Third Harmonic Output from a Pulsed Nd3+:YAG Laser

Journal	Data powered by TypesetProcedia Manufacturing
Publisher	Data powered by TypesetElsevier B.V.
ISSN	23519789
Open Access	Yes