Excimer Laser Crystallization of Sputter Deposited a-Si Films on Flexible Substrates

2004 ◽  
Vol 814 ◽  
Author(s):  
Yong Hoon Kim ◽  
Sung Kyu Park ◽  
Dae Gyu Moon ◽  
Won Keun Kim ◽  
Jeong In Han
Keyword(s):  
Excimer Laser ◽  
Laser Annealing ◽  
Rutherford Backscattering Spectrometry ◽  
Laser Energy ◽  
Dynamic Pressure ◽  
Excimer Laser Annealing ◽  
Flexible Polymer ◽  
Average Grain Size ◽  
Argon Concentration ◽  
Si Films

AbstractIn this report, excimer laser annealed polycrystalline silicon (poly-Si) films on flexible polymer substrates are investigated. The amorphous silicon (a-Si) films were first deposited on polycarbonate (PC) and polyethersulfone (PES) substrates by radio-frequency (RF) magnetron sputter and sequentially annealed by XeCl excimer laser annealing system (λ = 308 nm). The argon concentration of a-Si films which was estimated by Rutherford Backscattering Spectrometry (RBS) was found to be dependent on the dynamic pressure during the deposition process and the sputtering gas. Typically, the argon concentration of a-Si film was 1 ∼ 2% when the film was deposited using argon gas at 6 mTorr. After the annealing process, the average grain size of the poly-Si film annealed with laser energy density of 289 mJ/cm2was 400 nm estimated from transmission electron microscope (TEM) investigations.

Polycrystalline Silicon Films on SiO2 Substrate Treated by Excimer Laser Annealing

2013 ◽  
Vol 750-752 ◽  
pp. 946-951
Author(s):  
Chun Yan Duan ◽  
Bin Ai ◽  
Rong Xue Li ◽  
Chao Liu ◽  
Jian Jun Lai ◽  
...  
Keyword(s):  
Grain Size ◽  
Excimer Laser ◽  
Polycrystalline Silicon ◽  
Laser Annealing ◽  
Laser Energy ◽  
Chemical Vapor ◽  
Excimer Laser Annealing ◽  
Before And After ◽  
Si Films ◽  
Polycrystalline Silicon Films

Selected area laser-annealed polycrystalline silicon (p-Si) thin films were prepared by a 248 nm excimer laser. 1 μm thick p-Si films with grain size less than 100 nm were deposited on SiO2substrate by chemical vapor deposition using atmospheric pressure (APCVD). Grain sizes before and after annealing was examined by scanning electron microscopy (SEM) and the mechanism of grain growth was discussed in detail. The maximum grain size of a selected area laser-annealed p-Si film can be increased from 100 nm up to 2.9 μm on SiO2substrate by using appropriate laser energy densities. It indicated that silicon grains in laser-annealed regions had grown up competitively with three stages.

Excimer Laser Annealed Poly-Si TFT Technologies

1995 ◽  
Vol 377 ◽  
Author(s):  
Fujio Okumura ◽  
Kenji Sera ◽  
Hiroshi Tanabe ◽  
Katsuhisa Yuda ◽  
Hiroshi Okumura
Keyword(s):  
Energy Density ◽  
Leakage Current ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Laser Energy ◽  
Gate Insulator ◽  
Excimer Laser Annealing ◽  
Threshold Voltage Shift ◽  
Si Films ◽  
Current Reduction

ABSTRACTThis paper describes the excimer laser annealed (ELA) poly-Si TFT technologies in terms of excimer laser annealing of Si films, the leakage current, and the TFT stability. A laser energy density and a shot dependencies of TFT characteristics was analyzed by TEM, SEM, and Raman. The mobility increases with increasing not only the energy density but also the shot density. The mobility increase with the energy density is due to the grain size enlargement. On the other hand, the mobility increase up to 10 to 20 shots is due to a decrease of defects, including small grains, grain boundaries and defects inside grains. The contribution of grain-growth is small. The ELA TFT has a micro-offset structure to reduce the leakage current. Moreover, we have proposed a dynamic leakage current reduction structure. The combination of these technologies provides a sufficiently small leakage current for AMLCDs. The stability of the gate insulator was analyzed. The TFT shows negative threshold voltage shift under gate bias stress. This is due to water penetration and the subsequent field activated chemical reaction in the gate insulator. The dissociation of Si-OH bonds with hydrogen-bonded water was a fundamental contributor. The shift was suppressed sufficiently by hydrogen passivation. Obtained ELA TFTs;s have mobilities of over 100 cm2/Vsec, threshold voltages of less than 3 V, effective leakage currents of less than 10−13 A, and are stable more than 10 years.

Intensity-Modulated Excimer Laser Annealing to Obtain (001) Surface-Oriented Poly-Si Films on Glass: Molecular Dynamics Study

2008 ◽  
Author(s):  
Norie Matsubara ◽  
Tomohiko Ogata ◽  
Takanori Mitani ◽  
Shinji Munetoh ◽  
Teruaki Motooka
Keyword(s):  
Molecular Dynamics ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Excimer Laser Annealing ◽  
Intensity Modulated ◽  
Si Films

Large-Grain Doped Poly-Si Films Fabricated Using New Excimer Laser Annealing Technique

1992 ◽  
Vol 283 ◽  
Author(s):  
Hiroshi Iwata ◽  
Tomoyuki Nohda ◽  
Satoshi Ishida ◽  
Takashi Kuwahara ◽  
Keiichi Sano ◽  
...  
Keyword(s):  
Grain Size ◽  
Sheet Resistance ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Solidification Velocity ◽  
Excimer Laser Annealing ◽  
Arf Excimer Laser ◽  
Si Films

ABSTRACTThe grain size of phosphorous (P)-doped poly-Si film has been enlarged to about 5000 Å by controlling the solidification velocity of molten Si during ArF excimer laser annealing. The drastically enlarged grain has few defects inside the grain. It has been confirmed that control of the solidification velocity is effective for P-doped poly-Si similar to the case of non-doped poly-Si films. In addition, a sheet resistance of 80 Ω/□ (ρ = 4 × 10-4 Ω · cm) has been achieved for very thin (500 Å) films by recrystallizing PECVD P-doped a-Si films.

Low-Temperature Polycrystalline Silicon Thin-Film Transistors and Circuits on Flexible Substrates

MRS Bulletin ◽  
2006 ◽  
Vol 31 (6) ◽  
pp. 461-465 ◽  
Author(s):  
P.C. van der Wilt ◽  
M.G. Kane ◽  
A.B. Limanov ◽  
A.H. Firester ◽  
L. Goodman ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Laser Annealing ◽  
Defect Density ◽  
Solid Phase ◽  
Flexible Substrates ◽  
Full Potential ◽  
Laser Crystallization ◽  
Silicon Thin Film ◽  
Excimer Laser Annealing ◽  
Si Films

AbstractLow-defect-density polycrystalline Si on flexible substrates can be instrumental in realizing the full potential of macroelectronics. Direct deposition or solid-phase crystallization techniques are often incompatible with polymers and produce materials with high defect densities. Excimer-laser annealing is capable of producing films of reasonable quality directly on polymer and metallic substrates. Sequential lateral solidification (SLS) is an advanced pulsed-laser-crystallization technique capable of producing Si films on polymers with lower defect density than can be obtained via excimer-laser annealing. Circuits built directly on polymers using these SLS films show the highest performance reported to date.

Crystallinity Improvement of Small Grained Poly-Si Films by Excimer Laser Annealing for High Performance TFT's

1991 ◽  
Author(s):  
Takashi Noguchi ◽  
Hironori Tsukamoto ◽  
Toshiharu Suzuki ◽  
Haruko Masuya
Keyword(s):  
Excimer Laser ◽  
High Performance ◽  
Laser Annealing ◽  
Excimer Laser Annealing ◽  
Si Films

Ultra-Shallow Junction Formation by Excimer Laser Annealing of Ultra-Low Energy B Implanted in Si

2003 ◽  
Vol 765 ◽  
Author(s):  
G. Fortunato ◽  
L. Mariucci ◽  
V. Privitera ◽  
A. La Magna ◽  
S. Whelan ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Laser Annealing ◽  
Laser Energy ◽  
Laser Pulses ◽  
Low Energy ◽  
Excimer Laser Annealing ◽  
High Resolution Tem ◽  
Ultra Shallow Junctions ◽  
Dopant Redistribution ◽  
Melt Duration

AbstractFormation of ultra-shallow junctions by excimer laser annealing (ELA) of ultra-low energy (1keV –250 eV) B implanted in Si has been investigated. High resolution TEM has been used to assess the as-implanted damage and the crystal recovery following ELA. The electrical activation and redistribution of B in Si during ELA has been studied as a function of the laser energy density (melt depth), the implant dose and the number of laser pulses (melt duration). Under appropriate ELA conditions, ultra-shallow profiles, extending to a depth as low as 35 nm with an abrupt profile (2.5 nm/dec), have been achieved. A significant amount of the implanted dopant was lost from the sample following ELA. However, the dopant that was retained in crystal material was fully activated following rapid re-solidification. We developed a theoretical model, that considers the dopant redistribution during melting and regrowth, showing that the fraction of the implanted dopant not activated during ELA was lost from the sample through out diffusion. The lateral distribution of the implanted B following laser annealing has been studied with 2-D measurements, using selective etching and cross-section TEM on samples where the implanted dopant was confined by using test structures including windows opened in silicon dioxide masks and patterned gate stack structures.

Experimental Analysis for Low-Temperature Poly-Si Films Produced by Using the Excimer Laser Annealing Method

2006 ◽  
Vol 505-507 ◽  
pp. 277-282 ◽  
Author(s):  
Yu Ru Chen ◽  
Long Sun Chao
Keyword(s):  
Grain Size ◽  
Excimer Laser ◽  
Glass Substrate ◽  
Laser Annealing ◽  
Pulse Number ◽  
Sio2 Layer ◽  
Excimer Laser Annealing ◽  
Melt Pool ◽  
Si Films ◽  
Annealing Method

This paper is to investigate the effects on grain size of different working conditions for making poly Si films by using the excimer laser annealing method. In this research, a KrF excimer laser of 248 nm in wavelength is used to irradiate a-Si films of 0.1 μm in thickness on glass substrate to produce poly-Si ones. The control parameters are laser intensity (200~500 mJ/cm2), pulse number (1~10 shots) and coverage fraction (0~100%). Besides, the effect of a SiO2 layer is also studied, which is utilized as a heat-isolated zone located between the Si film and glass substrate. Average grain sizes from SEM photos are used to analyze the effects of these parameters. Purely from the heat transfer view, the Si film obtains more energy would have the slower cooling or solidification rate, which results in the larger grain. From the experimental results, if the melt pool is within the range of Si film or does not contact its neighboring layer (SiO2 layer or glass substrate), the more absorbed energy from the higher energy intensity, the larger pulse number or the bigger coverage fraction can have the larger average grain size. However, with large enough energy, the melt pool could go through the Si film and touch the lower layer. This would induce much more nuclei due to the homogeneous nucleation in the pool and the heterogeneous nucleation near the interface between the film and the neighboring layer. The resulting grain size is much smaller than that of the former one. The transition points of these two cases for different control parameters can be obtained from the experimental results in this study. When the energy from the laser is small, the SiO2 layer acts like a heat absorber and makes the grain size smaller than that of not having the SiO2 layer. On the other hand, when the energy is large, the SiO2 layer becomes a heat insulator and makes the grain size larger.

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