Simulation Of Polycrystalline Silicon Growth By Pulsed Excimer Laser Annealing

AbstractThe dynamic simulation of poly-Si film synthesis has been fulfilled by means of the overlapping irradiation of single- and double-pulsed XeCl excimer lasers shaped into the line beam. A novel model applied to the dynamic simulation is based on the homogeneous nucleation, and the growth and shrinkage velocity of Si grains. The results simulated with the single-pulsed XeCl excimer laser has reproduced the super lateral growth (SLG) phenomenon which occurs in the very narrow range of energy density (the near complete melt regime). The actual energy density dispersion within 5.3% allows us to visualize the multiformity of grain sizes in the cross sectional texture. Standing on the reproduction of the SLG phenomenon by the single-pulsed irradiation, we have obtained the practical knowledge of the growth process of larger grains by the double-pulsed irradiation. We intend that the first pulse has charge of completely melting and the second pulse has charge of adjusting the number of nuclei. The adjustment of the first pulse energy density rather than that of the second pulse energy density leads to the growth of huge columnar grains much larger than the thickness of the Si layer. For the double-pulsed irradiation, the influence of the worst energy density dispersion (each of double pulses has the same fluctuation as the single pulse) is much larger than that of the actual delay time jitter (within 2.5ns) in a sense of the multiformity of grain sizes.

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Microstructures of Luminescent nc-Si by Excimer Laser Annealing of a-Si:H

MRS Proceedings ◽

10.1557/proc-452-803 ◽

1996 ◽

Vol 452 ◽

Cited By ~ 2

Author(s):

Xinfan Huang ◽

Wei Wu ◽

Honghui Shen ◽

Wei Li ◽

Xiaoyuan Chen ◽

...

Keyword(s):

Energy Density ◽

Pulse Energy ◽

Laser Annealing ◽

Laser Wavelength ◽

Pulse Number ◽

Excimer Laser Annealing ◽

Pulse Energy Density ◽

Transmission Electron ◽

Ion Laser ◽

Si Films

AbstractWe have reported for the first time on visible photoluminescence (PL) in crystallized a-Si:H/a-SiNx:H multilayer structures by CW Ar ion laser annealing treatments. In this paper we present new results on visible PL from crystallized a-Si:H by using KrF excimer pulse laser (wavelength 248 nm) irradiating treatments. The transmission electron microscopy and Raman scattering studies reveal the microstructures of crystallized Si films, which depend on the pulse number and the pulse energy density of KrF laser. When the laser pulse energy density is higher than 520 mJ/cm2, the nanosized Si crystallites (nc-Si) can be formed from a-Si:H layers with a thickness of 100 nm and strong PL with a peak wavelength of 610 nm has been observed at room temperature.

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

Shinku ◽

10.3131/jvsj.43.1120 ◽

2000 ◽

Vol 43 (12) ◽

pp. 1120-1125 ◽

Cited By ~ 3

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

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

MRS Proceedings ◽

10.1557/proc-164-183 ◽

1989 ◽

Vol 164 ◽

Cited By ~ 5

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.

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XeCl Excimer Laser Annealing Used to Fabricate Poly-Si Tfts

MRS Proceedings ◽

10.1557/proc-71-435 ◽

1986 ◽

Vol 71 ◽

Cited By ~ 42

Author(s):

T. Sameshima ◽

S. Usui

Keyword(s):

Energy Density ◽

Excimer Laser ◽

Glass Substrate ◽

Laser Annealing ◽

Processing Temperature ◽

Excimer Laser Annealing ◽

Channel Mobility ◽

First Time ◽

Xecl Excimer Laser

AbstractMo-gate n-channel poly-Si TFTs have been fabricated for the first time at a low processing temperature of 26°C. 500 to 1000A thick a-Si:H was successfully crystallized by pulsed XeCl excimer laser (308nm) annealing without heating the glass substrate. The channel mobility of the TFT was 180 cm2/V.sec when the a-Si:H was annealed at energy density of 200 mJ/cm2.

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Epitaxial Regrowth of a-GaAs/(100) Silicon By Excimer Laser Annealing at 248 nm

MRS Proceedings ◽

10.1557/proc-53-187 ◽

1985 ◽

Vol 53 ◽

Author(s):

A. Christou ◽

T. Efthimiopoulos ◽

G. Kyriakidis ◽

C. Varmazis

Keyword(s):

Energy Density ◽

Ion Implantation ◽

Excimer Laser ◽

Field Effect ◽

Laser Annealing ◽

Field Effect Transistors ◽

Critical Energy ◽

Excimer Laser Annealing ◽

Epitaxial Regrowth ◽

Critical Energy Density

ABSTRACTExcimer laser annealing at 248 nm has resulted in the recrystallization of a-GaAs on (100) silicon. An AlAs encapsulation layer was found to be necessary to prevent the loss of arsenic during laser annealing. An energy density of 105 mJ/cm2 was the critical energy density which gave optimum results. Field effect transistors were fabricated on the regrown (100) GaAs utilizing ion implantation for the n-type channel, and resulted in a transconductance of 70–80 mS/mm.

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

MRS Proceedings ◽

10.1557/proc-693-i3.5.1 ◽

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.

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

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.371 ◽

2007 ◽

Vol 124-126 ◽

pp. 371-374 ◽

Cited By ~ 2

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.

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KRF excimer laser annealing for ultra shallow junction formation: approach for irradiation energy density reduction

11th IEEE International Conference on Advanced Thermal Processing of Semiconductors. RTP 2003 ◽

10.1109/rtp.2003.1249119 ◽

2004 ◽

Author(s):

K. Shibahara ◽

K. Kurobe ◽

Y. Ishikawa ◽

K. Kagawa ◽

Y. Niwatsukino ◽

...

Keyword(s):

Energy Density ◽

Excimer Laser ◽

Laser Annealing ◽

Excimer Laser Annealing ◽

Shallow Junction ◽

Density Reduction ◽

Irradiation Energy ◽

Junction Formation ◽

Krf Excimer Laser ◽

Irradiation Energy Density

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Excimer Laser Annealed Poly-Si TFT Technologies

MRS Proceedings ◽

10.1557/proc-377-877 ◽

1995 ◽

Vol 377 ◽

Cited By ~ 2

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.

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