A Novel Two-Pass Excimer Laser Crystallization Process to Obtain Homogeneous Large Grain Polysilicon

1999 ◽  
Vol 558 ◽  
Author(s):  
L. Mariucci ◽  
R. Carluccio ◽  
A. Pecora ◽  
V. Foglietti ◽  
G. Fortunato ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Crystallization Process ◽  
Laser Energy ◽  
Spatial Modulation ◽  
Lateral Growth ◽  
Laser Crystallization ◽  
First Pass ◽  
Wide Energy ◽  
Excimer Laser Crystallization ◽  
Polysilicon Tft

ABSTRACTNew approach to control the lateral growth mechanism through the opportune spatial modulation of the absorbed laser energy and with a two-pass excimer laser crystallization process is presented. In the first pass, spatial modulation of the light intensity has been obtained by irradiating the sample through a patterned mask in contact with the sample. Lateral growth is triggered when the irradiated regions are fully melted and a lateral extension of the grains in excess to 1 μm has been observed for samples irradiated at RT. In order to homogeneously crystallize the sample, the film can be re-irradiated (second pass) without the mask. By using opportune energy densities it can be induced a complete melting of the residual a-Si regions (masked areas during the first pass), while partially melting the polysilicon regions (unmasked areas during the first pass). Different mask geometries have been investigated and for optimized conditions, the sample area can be fully covered with laterally grown grains. The proposed novel technique can be rather attractive for polysilicon TFT fabrication, being characterized by only a two laser-shot process and wide energy density windows.

Excimer Laser Crystallization of Nanocrystalline Silicon Thin Films

2015 ◽  
Vol 1120-1121 ◽  
pp. 361-368
Author(s):  
Li Jie Deng ◽  
Wei He ◽  
Zheng Ping Li
Keyword(s):  
Thin Films ◽  
Energy Density ◽  
Excimer Laser ◽  
Silicon Film ◽  
Threshold Energy ◽  
Nanocrystalline Silicon ◽  
Lateral Growth ◽  
Laser Crystallization ◽  
Silicon Thin Films ◽  
Excimer Laser Crystallization

Nanocrystalline silicon (nc-Si) thin film on glass substrate is subjected to excimer laser crystallized by varying the laser energy density in the range of 50~600 mJ/cm2. The effect of excimer laser crystallization on the structure of silicon film is investigated using Raman spectroscopy, X-ray diffraction, atomic force microscopy and scanning electron microscopy. The results show that polycrystalline silicon thin films can be obtained by excimer laser crystallization of nc-Si films. A laser threshold energy density of 200 mJ/cm2 is estimated from the change of crystalline fraction and surface roughness of the treated films. The growth of grain is observed and the crystallization mechanism is discussed based on the super lateral growth model. The nanocrystalline silicon grains in the films act as seeds for lateral growth to large grains.

Excimer-Laser Crystallization of Si Films Via Bi-Directional Irradiation of Dual-Layer Films on Transparent Substrates

1995 ◽  
Vol 397 ◽  
Author(s):  
Jung H. Yoon ◽  
James S. Im
Keyword(s):  
Excimer Laser ◽  
Thermal Environment ◽  
Thermal Evolution ◽  
Bottom Layer ◽  
Lateral Growth ◽  
Laser Crystallization ◽  
Projection System ◽  
Substrate Heating ◽  
Excimer Laser Crystallization ◽  
Si Films

ABSTRACTIn this paper, we report on a new excimer-laser crystallization (ELC) method that is highly effective in extending the super-lateral growth (SLG) distance and which does not involve any preheating of the substrate. The technique utilizes bi-directional irradiation of a dual layer Si film stack (separated by an oxide layer) deposited on a quartz wafer. The top layer is irradiated with a projection system which transfers a mask image in order to produce grain-boundary-location-controlled (GLC) regions, and the bottom layer, upon irradiation with a uniform beam, acts as a medium that favorably affects the thermal evolution of the top layer. The technique is effective and attractive in that the heating is spatially and temporally localized in an optimal manner. The thermal environment required for extending the SLG distance, as is induced by the melting and solidification of the bottom layer, is physically regulated by the melting temperature of Si, and the enthalpy difference between liquid and solid can be used to initially store and subsequently release heat. Using the method, we were able to attain GLC regions with widths up to 10 μm in 1000-Å Si films without any substrate heating. We elaborate on the applicability of the method to various artificially controlled super-lateral growth (ACSLG) techniques, and discuss process optimization by means of varying the multilayer configuration.

Observation of super lateral growth in long pulse (170 ns) excimer laser crystallization of a-Si films

2003 ◽  
Vol 427 (1-2) ◽  
pp. 319-323 ◽  
Author(s):  
A. Pecora ◽  
R. Carluccio ◽  
L. Mariucci ◽  
G. Fortunato ◽  
D. Murra ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Lateral Growth ◽  
Laser Crystallization ◽  
Excimer Laser Crystallization ◽  
Si Films ◽  
Long Pulse

Super-lateral-growth regime analysis in long-pulse-duration excimer-laser crystallization of a-Si films on SiO 2

1999 ◽  
Vol 68 (6) ◽  
pp. 631-635 ◽  
Author(s):  
E. Fogarassy ◽  
S. de Unamuno ◽  
B. Prevot ◽  
P. Boher ◽  
M. Stehle ◽  
...  
Keyword(s):  
Pulse Duration ◽  
Excimer Laser ◽  
Lateral Growth ◽  
Laser Crystallization ◽  
Growth Regime ◽  
Excimer Laser Crystallization ◽  
Si Films ◽  
Long Pulse ◽  
Regime Analysis

Advanced excimer-laser crystallization process for single-crystalline thin film transistors

2003 ◽  
Vol 427 (1-2) ◽  
pp. 77-85 ◽  
Author(s):  
Ryoichi Ishihara ◽  
Paul Ch. van der Wilt ◽  
Barry D. van Dijk ◽  
Artyom Burtsev ◽  
J.W. Metselaar ◽  
...  
Keyword(s):  
Thin Film ◽  
Excimer Laser ◽  
Thin Film Transistors ◽  
Crystallization Process ◽  
Laser Crystallization ◽  
Single Crystalline ◽  
Excimer Laser Crystallization
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