Journal of Materials Science and Engineering B 3 (6) (2013) 346-351 Increase in Generation of Poly-Crystalline Silicon by Atmospheric Pressure Plasma-Assisted Excimer Laser Annealing Alexander Gredner 1 , Christoph Gerhard 1, 2 , Stephan Wieneke 1, 2 , Kai Schmidt 3 and Wolfgang Viöl 1, 2 1. Laboratory for Laser and Plasma Technologies, University of Applied Sciences and Arts, Göttingen 37085, Germany 2. Application Center for Plasma and Photonic, Fraunhofer Institute for Surface Engineering and Thin Films, Göttingen 37085, Germany 3. Coherent Laser Systems GmbH & Co. KG, Göttingen 37079, Germany Received: March 18, 2013 / Accepted: April 12, 2013 / Published: June 25, 2013. Abstract: In this work, a novel atmospheric pressure plasma-assisted excimer laser annealing method for increasing the generation efficiency of poly-crystalline silicon from amorphous silicon layers is presented. Here, both the plasma and the laser propagate coaxially in order to generate energetic synergies. The influence of different process gases and plasma discharge modes as well as the working distance were investigated. Depending on the particularly applied plasma, the crystalline area was increased by a factor of approx. 1.1 to 1.9, where the highest efficiency was observed when introducing an argon plasma beam to the annealing process. Key words: Excimer laser annealing, laser-plasma processes, amorphous silicon, polycrystalline silicon, display technology. 1. Introduction For a sensitive representation of images, modern flat screen displays are based on thin film transistors (TFT), where each pixel is supplied with variable voltages. The cost-efficient realisation of the required integrated circuits is achieved by the so-called system on glass (SOG) technique. Here, amorphous silicon (α-Si), which is gained from gaseous silane (SiH 4 ), is deposited onto a glass substrate. This α-Si layer is then converted into polycrystalline silicon (p-Si) in order to fabricate semiconducting channels [1]. Due to the comparatively low softening point of the used glass substrates, resulting in a thermal limitation of the process of T max ≈ 500-650 °C, low temperature poly silicon technology (LTPS) is applied [2]. Here, the application of pulsed excimer laser irradiation Corresponding author: Wolfgang Viöl, Dr., Prof. rer. nat., research fields: plasma and laser physics and technologies, E-mail: vioel@hawk-hhg.de. affects a short-time melting of the silicon layer without any significant heating of the glass substrate. In this context, several processes for large-scale crystallisation based on specifically shaped laser beams such as excimer-laser-annealing (ELA) allow the generation of large crystallite spots by single- or multi-pulse annealing [3]. In the case of ELA, the applied laser fluence Φ corresponds to the fluence which is required for melting the entire α-Si layer. Here, the silicon layer is molten except of minor polycrystalline zones at the silicon-glass interface. Starting at these zones, the lateral and columnar crystallisation, i.e. the generation of p-Si, takes place. As a result, the crystallites exceed the layer thickness of the initial silicon layer. This effect is known as super lateral growth (SLG) [2, 4], resulting in a high electron mobility within the p-Si layer and thus enabling faster TFT switching times [5]. ELA is applied for the production of active matrix liquid crystal display (AM-LCD)- or active matrix DAVID PUBLISHING D