Periodic grain-boundary formation in a poly-Si thin film crystallized by linearly polarized Nd:YAG pulse laser with an oblique incident angle

2005 ◽  
Vol 97 (1) ◽  
pp. 014904 ◽  
Author(s):  
Hirokazu Kaki ◽  
Susumu Horita
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Pulse Laser ◽  
Incident Angle ◽  
Boundary Formation ◽  
Linearly Polarized ◽  
Si Thin Film

Formation of periodic grain boundary in an Si thin film crystallized by a linearly polarized Nd:YAG pulse laser with an ultra sonic oscillator

2004 ◽  
Vol 808 ◽  
Author(s):  
Hirokazu Kaki ◽  
Takehiko Ootani ◽  
Susumu Horita
Keyword(s):  
Grain Boundary ◽  
Pulse Laser ◽  
Pulse Number ◽  
Novel Technique ◽  
Thermal Distribution ◽  
Irradiation Pulse ◽  
Linearly Polarized ◽  
Boundary Location ◽  
Amorphous Si ◽  
Si Thin Film

ABSTRACTIn order to obtain a large silicon (Si) grain and to control the location of its boundary in a Si film melting-crystallized by a pulse laser, we have proposed to use periodic thermal distribution spontaneously induced by irradiation of a linearly polarized laser beam. We estimated the suitable amorphous Si (a-Si) thickness taking account of multiple reflection theoretically and confirmed it experimentally. Also, we proposed a novel technique to reduce the irradiation pulse number to control the grain boundary location stably in the crystallized Si film, in which the elastic wave was generated on the surface of a-Si film prior to melting-crystallization by using an ultra sonic oscillator. Owing to this technique, we can control the grain boundary location periodically with only 1 pulse irradiation in the crystallized Si film.

Influence of the Beam Irradiation Condition With Oblique Incidence on Crystallization of an Si film by a Linearly Polarized Pulse Laser

2002 ◽  
Vol 715 ◽  
Author(s):  
Yasunori Nakata ◽  
Hirokazu Kaki ◽  
Susumu Horita
Keyword(s):  
Grain Boundary ◽  
Film Thickness ◽  
Pulse Laser ◽  
Oblique Incidence ◽  
Incident Angle ◽  
Pulse Number ◽  
Experimental Results ◽  
Irradiation Condition ◽  
Beam Irradiation ◽  
Linearly Polarized

AbstractWe investigated influence of the beam irradiation conditions with oblique incidence on crystallization of an Si film by a linearly polarized pulse laser in order to enlarge the periodic width of grain boundary. The irradiation conditions are fluence, pulse number and film thickness. We can obtain the periodic width of about 900 nm by increasing the incident angle to 25°. The experimental results suggest that the pulse number and the film thickness should be controlled properly as well as fluence in order to produce large grain stably for the oblique incidence. The detail of these conditions was discussed.

Periodic Alignment of Silicon Dot Fabricated by Linearly Polarized Nd:YAG Pulse Laser

2006 ◽  
Vol 910 ◽  
Author(s):  
Kensuke Nishioka ◽  
Susumu Horita
Keyword(s):  
Thin Film ◽  
Energy Density ◽  
Laser Beam ◽  
Density Distribution ◽  
Pulse Laser ◽  
Incident Beam ◽  
Sio2 Film ◽  
Energy Density Distribution ◽  
Linearly Polarized ◽  
Si Thin Film

AbstractPeriodically aligned submicron Si dots were fabricated by only irradiating linearly polarized Nd:YAG pulse laser to the amorphous silicon (a-Si) thin film deposited on silicon dioxide (SiO2) film. Interference between the incident beam and the scattered surface wave leads to the spatial periodicity of beam energy density distribution on the surface of the irradiated samples. The a-Si thin film was melted by laser beam, and then, the molten thin Si film was split and condensed due to its surface tensile according to the periodic energy density distribution. The polycrystalline Si (poly-Si) fine lines were formed periodically. After the first irradiation, the sample was rotated by 90o, and the laser beam was irradiated. The periodic energy density distribution was generated on the Si fine lines. Then, the lines were split off and condensed according to the periodic energy density distribution, and the periodically aligned submicron Si dots were fabricated on the SiO2 film.

Location Control of Laterally Columnar Si Grains by Dual-Beam Excimer-Laser Melting of Si Thin-Film

2000 ◽  
Vol 621 ◽  
Author(s):  
Ryoichi Ishihara
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Heat Source ◽  
Grain Boundaries ◽  
Excimer Laser ◽  
Laser Melting ◽  
Dual Beam ◽  
Single Grain ◽  
Free Area ◽  
Si Thin Film

ABSTRACTThe offset of the underlying TiW is introduced in the island of Si, SiO2 and TiW on glass. During the dual-beam excimer-irradiation to the Si and the TiW, the offset in TiW acts as an extra heat source, which melts completely the Si film near the edge, whereas the Si inside is partially melted. The laterally columnar Si grains with a length of 3.2 μm were grown from the inside of the island towards the edge. By changing the shape of the edge, the direction of the solidification of the grain was successfully controlled in such a way that the all grain-boundaries are directed towards the edge and a single grain expands. The grain-boundary-free area as large as 4 μm × 3 μm was obtained at a predetermined position of glass.

Activation Energy Analysis of Dark and Laser Illuminated I-V Characteristics of Thin-Film Poly Silicon Solar Cells

2010 ◽  
Author(s):  
M. Boostandoost ◽  
U. Kerst ◽  
C. Boit
Keyword(s):  
Thin Film ◽  
Activation Energy ◽  
Solar Cells ◽  
Solar Cell ◽  
Grain Boundary ◽  
Thin Film Solar Cell ◽  
Reverse Bias ◽  
Reverse Current ◽  
Thin Film Solar Cells ◽  
Si Thin Film

Abstract The temperature dependence of photocurrent of polycrystalline Si (poly-Si) thin-film solar cells on glass with interdigitated mesa structure has been locally investigated using Infrared Light Beam Induced Current (IR-LBIC) in the temperature range of -25 to +70 °C. The temperature dependence of electrical characteristics of poly-Si thin-film solar cells in reverse bias has been also analysed and compared with the monocrystalline thin-film solar cells. The poly-Si solar cell shows a temperature coefficient (TC) for the photocurrent of around +0.8 and +0.6 %/°C in the grain interior and grain boundary, respectively. The activation energy of the reverse current and also the photocurrent due to the IR laser stimulation has been evaluated, which provide information about traps and their energy levels in the absorber layer of the poly-Si thin-film solar cell. The obtained average value of the activation energy associated with the photocurrent of the poly-Si cell suggests the existence of a shallow acceptor level at around 0.045 eV in the grain boundary and 0.062 eV in the grain interior of the absorber layer of the poly-Si thin-film solar cell. The activation energies of the reverse current for poly-Si and monocrystalline cells have been calculated when the device is biased at -1 and -2 V and the results compared with the activation energy of the saturation current obtained from extrapolation of the I-V curve in the SRH (Shockley-Read-Hall) regime. The results show strong voltage dependence. In both cases the activation energy of the reverse current decreases in the reverse bias voltage, approaching the values obtained from the photocurrent.

NBTI-Stress Induced Grain-Boundary Degradation in Low-Temperature Poly-Si Thin-Film Transistors

2007 ◽  
Author(s):  
Chih-Yang Chen ◽  
Ming-Wen Ma ◽  
Wei-Cheng Chen ◽  
Hsiao-Yi Lin ◽  
Kuan-Lin Yeh ◽  
...  
Keyword(s):  
Thin Film ◽  
Low Temperature ◽  
Grain Boundary ◽  
Thin Film Transistors ◽  
Si Thin Film
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