We studied a new method of Ni-induced crystallization of amorphous silicon ͑a-Si͒ through a silicon-nitride (SiN x ) cap layer. A 0.5 nm of Ni layer was deposited on the SiN x /a-Si layers and then this was annealed in a rapid thermal annealing system. The Ni diffused through the cap layer and formed the NiSi 2 nuclei. Then, disk-shaped grains were grown from these nuclei. The grain size is between 20 and 90 m, and the surface roughness of the poly-Si is 0.76 nm, which is smoother than that ͑0.96 nm͒ of the poly-Si without a cap layer.Polycrystalline silicon ͑poly-Si͒ on glass is a promising material for large-area electronics such as active-matrix liquid crystal displays, active-matrix organic light emitting diodes, and solar cells.To improve the quality of the poly-Si on insulator, several approaches have been conducted on the crystallization of amorphous silicon ͑a-Si͒ including a capping layer on it. For example, in zonemelting recrystallization of Si with a strip heater, an encapsulation layer is necessary and appears to play three major roles: to achieve a smooth surface, to prevent agglomeration, and to induce preferred orientation ͑100͒ texture. 1 To control the lateral growth of excimer laser crystallization poly-Si through lateral thermal gradients, three different patterned capping layers have been used: antireflective (SiO 2 ), heat-sink ͑silicon nitride͒, and reflective ͑metal͒ capping layers. 2 On the other hand, Ni-induced crystallization using various Ni solutions 3,4 and an ultrathin Ni layer of ϳ10 13 cm Ϫ2 has been studied. 5,6 Recently, high quality poly-Si on insulator by metal-induced lateral crystallization ͑MILC͒ has been demonstrated. 6,7 However, the metal layer for the conventional metal induced crystallization ͑MIC͒, and/or MILC poly-Si, was deposited at least on a portion of the surface on the a-Si. In this case, the metal-contacted region on the a-Si for metal-induced crystallization is contaminated by metal impurities.To reduce metal contamination and to have uniform grain size with clean and smooth surface, we have studied Ni-induced crystallization of a-Si using a thin Ni layer on a SiN x /a-Si:H, where the capping layer (SiN x ) is a filter for metal diffusion.We deposited an a-Si:H layer first on glass and then SiN x by plasma-enhanced chemical vapor deposition ͑PECVD͒. The thicknesses of a-Si:H and SiN x are 100 and 150 nm, respectively. The 0.5 nm thick Ni layer was deposited using radio frequency sputtering with a very low power density and patterned to have a square of 360 ϫ 360 m. Figure 1 shows a schematic illustration of a Ni/SiN x /a-Si structure for Ni-induced crystallization. The samples were heated by using a rapid thermal annealing ͑RTA͒ system in N 2 ambient. The temperatures during the heating, cooling, and keeping the sample were controlled. The first step is to dehydrogenate the a-Si:H and SiN x at 430°C for 1 h. The hydrogen atoms in the a-Si:H and SiN x are effused out and the film is changed to a hydrogen-free amorphous silicon. The second step is a pulsed hea...

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An excimer-laser-based two-shot sequential lateral solidification (TS-SLS) process has been developed to fabricate 30" FHD (1920xRGBx1080) AMOLED TVs using both 2D projection and line-scan SLS systems. We have optimized (1) the microstructure of TS-SLS processed polycrystalline materials, (2) the geometry of driving TFTs to minimize non-uniformity of the pixel brightness and (3) the off-bias TFT aging process to reduce the leakage current. This result verifies that the TS-SLS process can be utilized to make large area AMOLED TVs without any laser related mura.

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In this study, we propose a new low temperature polycrystalline silicon thin film transistor structure with good driving and reliability characteristics. The structure was proposed through TCAD simulation and verified through several simulation models. Thereafter, actual devices were manufactured to prove that characteristics were improved.