Polycrystalline Silicon Single Electron Island by Excimer Laser Irradiation on a-Si Film

1998 ◽  
Vol 507 ◽  
Author(s):  
C-M Park ◽  
J-H Jeon ◽  
M-S Lim ◽  
J-S Yoo ◽  
M-K Han
Keyword(s):  
Quantum Dot ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Laser Energy ◽  
Single Electron ◽  
Excimer Laser Annealing ◽  
Fine Grain ◽  
Si Quantum Dot ◽  
Laser Windows ◽  
Temperature Operating

ABSTRACTWe propose a novel fabrication method for a room temperature operating single-electron memory using the size and location controlled poly-Si island by lithographic technique and excimer laser annealing.We have patterned tip shaped excimer laser windows and irradiated laser energy through windows for crystallizing amorphous silicon. As a result of laser energy, the poly-Si grains are growing from patterned window side so that the fine grain and isolated large poly-Si quantum dot are inherently formed by well-known ACSLG regime. The oxidation was then performed by RTP at 950 °C for 30 seconds in order to isolate quantum island and fine poly-Si grains for quantum dot. The peaks of the poly-oxide along the poly-Si grain boundaries were lowered during that oxidation and isolated the poly-Si grains and made oxide barriers.

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.

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.

Melting and resolidification dynamics of a-Si and poly-Si thin films during excimer laser annealing

1999 ◽  
Vol 558 ◽  
Author(s):  
Mutsuko Hatano ◽  
Seungjae Moon ◽  
Minghong Lee ◽  
Kenkichi Suzuki ◽  
Costas P. Grigoropoulos
Keyword(s):  
Excimer Laser ◽  
Laser Annealing ◽  
Laser Energy ◽  
Electrical Conductance ◽  
Temperature History ◽  
Maximum Temperature ◽  
Excimer Laser Annealing ◽  
Complete Melting ◽  
In Situ Experiments ◽  
Melting Regime

ABSTRACTThe liquid-solid interface motion and the temperature history of thin Si films during excimer laser annealing are observed by in-situ experiments combining time-resolved (∼Ins) electrical conductance, optical reflectance/transmittance at visible and near-IR wavelength, and thermal emission measurements. The existence of partial and complete melting regimes is elucidated. In the partial melting regime, the maximum temperature remains close to the melting point of aSi, since the laser energy is consumed on the latent heat of phase-change. In the complete melting regime, substantial supercooling, followed by homogeneous nucleation is observed. These phase transformations are consistent with the recrystallized poly-Si morphologies.

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.

scholarly journals Crystallization of Amorphous Silicon via Excimer Laser Annealing and Evaluation of Its Passivation Properties

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3335
Author(s):  
Sanchari Chowdhury ◽  
Jinsu Park ◽  
Jaemin Kim ◽  
Sehyeon Kim ◽  
Youngkuk Kim ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Thermal Annealing ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Laser Energy ◽  
Ultra Violet ◽  
Uv Laser ◽  
Excimer Laser Annealing ◽  
Cell Efficiency ◽  
Deep Uv

The crystallization of hydrogenated amorphous silicon (a-Si:H) is essential for improving solar cell efficiency. In this study, we analyzed the crystallization of a-Si:H via excimer laser annealing (ELA) and compared this process with conventional thermal annealing. ELA prevents thermal damage to the substrate while maintaining the melting point temperature. Here, we used xenon monochloride (XeCl), krypton fluoride (KrF), and deep ultra-violet (UV) lasers with wavelengths of 308, 248, and 266 nm, respectively. Laser energy densities and shot counts were varied during ELA for a-Si:H films between 20 and 80 nm thick. All the samples were subjected to forming gas annealing to eliminate the dangling bonds in the film. The ELA samples were compared with samples subjected to thermal annealing performed at 850–950 °C for a-Si:H films of the same thickness. The crystallinity obtained via deep UV laser annealing was similar to that obtained using conventional thermal annealing. The optimal passivation property was achieved when crystallizing a 20 nm thick a-Si:H layer using the XeCl excimer laser at an energy density of 430 mJ/cm2. Thus, deep UV laser annealing exhibits potential for the crystallization of a-Si:H films for TOPCon cell fabrication, as compared to conventional thermal annealing.

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.

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 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.

Single-Shot Excimer Laser Annealing and In Process Ellipsometry Analysis for Ultra Shallow Junctions

2002 ◽  
Vol 717 ◽  
Author(s):  
T. Noguchi ◽  
G. Kerrien ◽  
T. Sarnet ◽  
D. Débarre ◽  
J. Boulmer ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Spectroscopic Ellipsometry ◽  
Laser Annealing ◽  
Laser Energy ◽  
Process Analysis ◽  
Single Shot ◽  
Excimer Laser Annealing ◽  
Dopant Activation ◽  
The Difference ◽  
Ultra Shallow Junctions

AbstractSingle-shot Excimer Laser Annealing (ELA) was performed onto Si surface that was previously B+ implanted with or without Ge+ pre-amorphization. As a result, p+ type USJ (Ultra-Shallow Junction) has been formed. In process analysis, using Infrared Spectroscopic Ellipsometry (IR-SE) has been performed and compared with conventional 4-point probe method. Also, the corresponding crystallinity for the USJ of Si surface has been studied using Ultraviolet-Visible (UV-Vis) Spectroscopic Ellipsometry. In the case of pre-amorphization by Ge+ implantation, the laser energy density threshold required for melting the surface, and therefore for electrical activation, decreased drastically because of the difference in the thermodynamic properties of the amorphized Si. Estimation of the junction depth shows a shallower junction when using UV-SE, as compared to IR-SE. This can be explained by the fact that, in the UV range, the crystallinity of the top layer is predominant while IR-SE is more sensitive to dopant activation. This efficient single-shot ELA is a candidate for the USJ formation for sub-0.1 νm CMOS transistors. The effective method for investigating the activation state related to the crystallinity by using UV-SE and IR-SE is expected to apply as a non-contact analytical tool for USJ formation.

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.

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