Fast-Pulse Excimer-Laser-Induced Processes in a-Si:H

1989 ◽  
Vol 164 ◽  
Author(s):  
K. Winer ◽  
R.Z. Bachrach ◽  
R.I. Johnson ◽  
S.E. Ready ◽  
G.B. Anderson ◽  
...  
Keyword(s):  
Energy Density ◽  
Excimer Laser ◽  
Impurity Concentration ◽  
Laser Annealing ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Excimer Laser Annealing ◽  
Near Surface ◽  
Pulse Excimer Laser ◽  
Fast Pulse

AbstractThe effects of fast-pulse excimer laser annealing of a-Si:H were investigated by measurements of electronic transport properties and impurity concentration depth profiles as a function of incident laser energy density. The dc dark conductivity of laser-annealed, highly-doped a-Si:H increases by a factor of ∼350 above a sharp laser energy density threshold whose magnitude increases with decreasing impurity concentration and which correlates with the onset of hydrogen evolution from and crystallization of the near-surface layer. The similarities between the preparation and properties of laser-crystallized a-Si:H and pc-Si:H are discussed.

Effect of Excimer Laser Annealing on Optical Properties of GaN Films Deposited by R.F. Magnetron Sputtering

2001 ◽  
Vol 693 ◽  
Author(s):  
Man Young Sung ◽  
Woong-Je Sung ◽  
Yong-Il Lee ◽  
Chun-Il Park ◽  
Woo-Boem Choi ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Density ◽  
Magnetron Sputtering ◽  
Buffer Layer ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Excimer Laser Annealing ◽  
Zno Buffer Layer

Abstract:GaN thin films on sapphire were grown by RF magnetron sputtering with ZnO buffer layer. The tremendous mismatch between the lattices of GaN and sapphire can be partly overcome by the use of thin buffer layer of ZnO. The dependence of GaN film quality on ZnO buffer layer was investigated by X-ray diffraction(XRD). The properties of the sputtered GaN are strongly dependent on ZnO buffer layer thickness. The optimum thickness of ZnO buffer layer is around 30nm. Using XRD analysis, we have found the optimal substrate temperature which can grow high quality GaN thin film. In addition, the effect of excimer laser annealing(ELA) on structural and electrical properties of GaN thin films was investigated. The surface roughness and images according to the laser energy density were investigated by atomic force microscopy(AFM) and it was confirmed that the crystallization was improved by increasing laser energy density.

Aligned Polycrystalline Silicon Array Thin Film by XeCl Excimer Laser Annealing for AMOLED Displays

2007 ◽  
Vol 124-126 ◽  
pp. 371-374 ◽  
Author(s):  
C.N. Chen ◽  
G.M. Wu ◽  
W.S. Feng
Keyword(s):  
Thin Film ◽  
Energy Density ◽  
Excimer Laser ◽  
Polycrystalline Silicon ◽  
Laser Annealing ◽  
Laser Energy ◽  
Annealing Atmosphere ◽  
Excimer Laser Annealing ◽  
Overlap Ratio ◽  
Xecl Excimer Laser

Low temperature polycrystalline silicon (LTPS) thin film transistors (TFTs) are demanded to fabricate high performance liquid crystal displays (LCD) and organic light-emitting diode displays (OLED). The mobility of poly-Si TFT can be two orders of magnitude higher than that of amorphous Si (a-Si) TFT. Excimer laser annealing has been studied to be the most promising technology to meet the stringent requirement in high speed operation. The process parameters were identified as a-Si thickness, laser energy density, overlap ratio, annealing atmosphere and pre-clean condition. The a-Si layer of 40-50 nm was deposited by plasma enhanced chemical vapor deposition (PECVD). The XeCl excimer laser was irradiated on the a-Si film at room temperature under N2 or N2/O2 environment. The energy density ranged 250-400 mJ/cm2, and the overlap ratio was 95-99%. The highly aligned poly-Si array thin film could be obtained. The grain size has been about 0.31x0.33 μm2, and the regular arrangement in poly-Si grains was discussed. In addition, the PMOS TFT has been fabricated from the aligned poly-Si array. The mobility was as high as 100 cm2/Vs and the sub-threshold swing was around 0.24 V/dec. The threshold voltage was -1.25 V and the on/off current ratio was about 106.

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.

scholarly journals Crystal Growth of Low-Temperature Processed Poly-Si by Excimer Laser Annealing. Dependences of Poly-Si Grain on Energy Density and Shot Number.

Shinku ◽  
2000 ◽  
Vol 43 (12) ◽  
pp. 1120-1125 ◽  
Author(s):  
Naoto MATSUO ◽  
Hisashi ABE ◽  
Naoya KAWAMOTO ◽  
Ryouhei TAGUCHI ◽  
Tomoyuki NOUDA ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Energy Density ◽  
Low Temperature ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Excimer Laser Annealing ◽  
Shot Number

Formation of Q-carbon by adjusting sp3 content in diamond-like carbon films and laser energy density of pulsed laser annealing

Carbon ◽  
2020 ◽  
Vol 167 ◽  
pp. 504-511 ◽  
Author(s):  
Hiroki Yoshinaka ◽  
Seiko Inubushi ◽  
Takanori Wakita ◽  
Takayoshi Yokoya ◽  
Yuji Muraoka
Keyword(s):  
Energy Density ◽  
Laser Annealing ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Carbon Films ◽  
Laser Energy Density ◽  
Diamond Like Carbon ◽  
Pulsed Laser Annealing

Discharge-Pumped VUV F2 Molecular Laser Annealing of Heavily Se+-Implanted GaAs

1993 ◽  
Vol 316 ◽  
Author(s):  
Hajime Shibata ◽  
Yunosuke Makita ◽  
Kawakatsu Yamada ◽  
Yutaka Uchida ◽  
Sabro Satoh
Keyword(s):  
Energy Density ◽  
Raman Scattering ◽  
Laser Annealing ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Furnace Annealing ◽  
Implantation Energy ◽  
Molecular Laser ◽  
First Time ◽  
Ion Implanted

ABSTRACTThe capability of discharge-pumped vacuum ultraviolet F2 molecular laser for laser annealing of heavily ion implanted semiconductor was demonstrated for the first time using Se+ heavily ion implanted GaAs. Cr-doped semi-insulationg GaAs wafers were used as the substrates, and the Se+ implantation energy and dose were controlled to 100 keV and 1× 1015 cm-2, respectively. Samples were annealed using a F2 molecular laser ( wavelength = 157 nm ) with a single pulse ( width ~ 20 ns ) in the energy density range from 200 to 800 mJ/cm2 in a nitrogen atmosphere. In addition, furnace annealing was done on separate samples at 850 ºC for 20 minutes in a purified hydrogen atmosphere for comparison. Characterization of the samples was carried out using Raman scattering and ellipsometry. The laser annealed samples exhibited intense Raman scattering LO phonon peaks whose intensity increased with increasing laser power density, whereas the furnace annealed samples exhibited a very weak LO phonon peak. It was demonstrated for the first time that VUV photons can be very effective in annealing ion implantation damage as compared with conventional furnace annealing. The behavior of Raman scattering spectra as a function of laser energy density was explained quantitatively by a “spatial correlation” model. The model made it possible to estimate the average size of the recovered crystal regions in samples for any given laser energy density.

Laser annealing of laser additive–manufactured Ni-Ti structures: An experimental–numerical investigation

2016 ◽  
Vol 232 (6) ◽  
pp. 1054-1067 ◽  
Author(s):  
S Shiva ◽  
IA Palani ◽  
CP Paul ◽  
B Singh
Keyword(s):  
Energy Density ◽  
Laser Annealing ◽  
Laser Energy ◽  
Experimental Studies ◽  
Mechanical Systems ◽  
Laser Energy Density ◽  
Phase Transformation Temperature ◽  
Scanning Calorimetry ◽  
Homogeneous Microstructure ◽  
Micro Electro Mechanical Systems

Tailored structures of Ni-Ti shape memory alloys for micro-electro-mechanical systems can be fabricated using laser additive manufacturing, and requisite homogeneous microstructure for predictive design and fabrication of micro-electro-mechanical systems devices can be achieved by annealing. Investigation has been performed on the laser annealing of laser additive–manufactured Ni-Ti structures using a pulsed green laser through numerical simulation and experimental studies. The parametric dependence showed that a laser energy density of 1100 mJ cm−2 has a considerable influence in annealing of Ni-Ti structures. The surface morphology, phase transformation temperature and microstructure of laser-annealed Ni-Ti structures were studied with scanning electron microscopy, differential scanning calorimetry, X-ray diffraction and atomic force microscopy. Laser energy density of 1100 mJ cm−2 was used for annealing the samples as identified in the simulation. Surface annealing of Ni-Ti led to a uniform surface of the material with an increase in grain size and surface roughness. A decrease in the micro-hardness of the samples was obtained as a result of laser annealing. Thus, the investigations demonstrated the improved properties of laser additive–manufactured Ni-Ti structures by laser annealing.

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.

Boron distribution in silicon after multiple pulse excimer laser annealing

2005 ◽  
Vol 87 (8) ◽  
pp. 081901 ◽  
Author(s):  
E. V. Monakhov ◽  
B. G. Svensson ◽  
M. K. Linnarsson ◽  
A. La Magna ◽  
M. Italia ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Laser Annealing ◽  
Excimer Laser Annealing ◽  
Multiple Pulse ◽  
Pulse Excimer Laser ◽  
Boron Distribution

Excimer Laser Induced Crystallization of Amorphous Silicon Near Threshold

1989 ◽  
Vol 157 ◽  
Author(s):  
R.Z. Bachrach ◽  
K. Winer ◽  
J.B. Boyce ◽  
F.A. Ponce ◽  
S.E. Ready ◽  
...  
Keyword(s):  
Energy Density ◽  
Laser Beam ◽  
Amorphous Silicon ◽  
Excimer Laser ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Square Root ◽  
Threshold Behavior ◽  
Sharp Threshold ◽  
Induced Crystallization

ABSTRACTUsing a suitably homogenized excimer laser beam, we have shown that the threshold for crystallization of amorphous silicon is well defined and exhibits a square root dependence on the laser energy density above threshold. This sharp threshold behavior can be exploited in a number of ways.

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