Polysilicon Films Formed On Alumina By Aluminium Induced Crystallization Of Amorphous Silicon

2006 ◽  
Vol 910 ◽  
Author(s):  
Etienne Pihan ◽  
Abdelilah Slaoui ◽  
Claude Maurice
Keyword(s):  
Amorphous Silicon ◽  
Grain Orientation ◽  
Coincident Site Lattice ◽  
Grain Structure ◽  
Structural Quality ◽  
Orientation Imaging ◽  
Polysilicon Films ◽  
Si Films ◽  
Induced Crystallization

AbstractWe investigated the structural quality of polysilicon films fabricated by the aluminium induced crystallization (AIC) of amorphous silicon on alumina substrates. We analyzed the overall crystallographic quality of the poly-Si films in terms of grain size distribution and grain orientation versus crystallization temperature. For these studies, we used extensively the orientation imaging micrograph (OIM) technique, a very powerful tool that allows elucidating the inner-grain structure, the grain boundaries, the grain orientation. From our analysis, we may conclude that the polysilicon films formed by AIC on alumina substrates have the following features: (i) for all investigated temperatures, most of the silicon grains have a deviation angle from (100) crystallographic orientation between 5 and 25°; (ii) increasing the annealing temperature tends to decrease the (100) preferred orientation; (iii) the angular boundary distribution revealed that the main defects are those that have been observed inside isolated dentrites, namely low angle boundaries (<2°) and coincident site lattice boundaries such as Σ3, Σ9 and Σ27.

Lateral Epitaxial Growth of Thick Polysilicon Films on Oxidized 3-Inch Wafers

1982 ◽  
Vol 13 ◽  
Author(s):  
G. K. Celler ◽  
Mcd. Robinson ◽  
D. J. Lischner ◽  
T. T. Sheng
Keyword(s):  
Epitaxial Growth ◽  
Structural Characterization ◽  
High Intensity ◽  
Structural Quality ◽  
Grown Film ◽  
Crystallization Procedure ◽  
Polysilicon Films ◽  
Si Films ◽  
Crystallization From The Melt

ABSTRACTRecently we reported the first successful crystallization from the melt of 15,μm thic Si films on SiO2. In this technique of Lateral Epitaxial Growth over Oxide (LEGO), crystallization is initiated at seeding vias in SiO2 and propagates over the amorphous insulator, resulting in high structural quality of the grown film. Uniform and bow-free crystallization of complete 3-inch wafers occurs in <60 sec in a special furnace, with wafers placed between a bank of high intensity tungsten halogen lamps and a water cooled base.In this paper we provide further details of crystallization procedure and new structural characterization data. The mechanism of LEGO crystallization and its limitations are also discussed.

Crystallization of Tin-Implanted Amorphous Silicon Thin Films

1992 ◽  
Vol 279 ◽  
Author(s):  
Fuyu Lin ◽  
Miltiadis K. Hatalis
Keyword(s):  
Amorphous Silicon ◽  
Crystallization Process ◽  
Silicon Films ◽  
Grain Structure ◽  
Crystallization Time ◽  
Silicon Thin Films ◽  
Fine Grain ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Si Films

ABSTRACTThe crystallization of Sn-implanted amorphous silicon was studied as a function of tin implant dose and annealing conditions by transmission electron microscopy. The films were implanted at an energy of 110 keV with a dose in the range of 5 × 1014 to 5×1016 cm−2 and were annealed at a temperature in the range of 450°C to 550°C. An enhanced rate of crystallization in amorphous Si-Sn films compared to the non-implanted amorphous silicon films during thermal annealing was observed. The crystallization process of Si films implanted with tin at a dose of 2.5×1016 cm−2 or less is very similar to unimplanted silicon films except higher nucleation rates and shorter crystallization time were observed with increasing tin dose. Films implanted with tin at a dose of 2.5×1016 cm−2 or more display extremely rapid crystallization (3 hours at 450°C) and very fine grain structure (10 nm); no substantial grain growth has been observed during lurther annealing, but some single crystal-like areas were formed. In-situ annealing of silicon implanted to 5×1016 cm−2 showed that the crystallization process is enhanced by the formation of the liquid tin phase.

The effect of substrate temperature and interface oxide layer on aluminum induced crystallization of sputtered amorphous silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
Maruf Hossain ◽  
Husam Abu-Safe ◽  
Marwan Barghouti ◽  
Hameed Naseem ◽  
William D. Brown
Keyword(s):  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Oxide Layer ◽  
Environmental Scanning ◽  
X Ray ◽  
Layer Sequence ◽  
Si Films ◽  
Induced Crystallization ◽  
Al Oxide ◽  
Aluminum Induced Crystallization

ABSTRACTThe effect of substrate temperature and interface oxide layer on aluminum induced crystallization (AIC) of amorphous silicon (a-Si) is investigated. The effect of substrate temperature on the AIC process was studied by changing the deposition temperate of a-Si from 200 to 300°C in a Al/a-Si/glass configuration. To study the effect of interface oxide on AIC, samples with a-Si/Al/glass, a-Si/Al-oxide/Al/glass, and Al/Si-oxide/a-Si/glass configurations were prepared at a fixed substrate temperature. The samples were annealed in the temperature range from 300°C to 525°C for different periods of time. The X-ray diffraction (XRD) patterns confirmed the crystallization of the a-Si films in the various configurations. From the analysis, we report that crystallization of a-Si happen at 350°C annealing temperature in the Al/a-Si/glass configuration. However, with or without the presence of Si-oxide at the interface, crystallization saturated after annealing for 20 minutes at 400°C. On the other hand, when Al-oxide is present at the interface, higher annealing temperatures and longer annealing times are required to saturate the crystallization of a-Si. Environmental Scanning Electron Microscope (ESEM) and Energy Dispersive X-Ray (EDX) mapping were used to study the surface morphology as well as the layer sequence after crystallization. This analysis revealed that Si-Al layer-exchange happens regardless of the deposited film configuration.

Polycrystalline Silicon Films Formed by Solid-Phase Crystallization of Amorphous Silicon: the Substrate Effects on Crystallization Kinetics and Mechanism

1996 ◽  
Vol 424 ◽  
Author(s):  
Y.-H. Song ◽  
S.-Y. Kang ◽  
K. I. Cho ◽  
H. J. Yoo ◽  
J. H. Kim ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solid Phase Crystallization ◽  
Substrate Effects ◽  
Random Nucleation ◽  
Pressure Chemical ◽  
Si Films ◽  
Polycrystalline Silicon Films ◽  
Induced Crystallization

AbstractThe substrate effects on the solid-phase crystallization of amorphous silicon (a-Si) have been extensively investigated. The a-Si films were prepared on two kinds of substrates, a thermally oxidized Si wafer (SiO2/Si) and a quartz, by low-pressure chemical vapor deposition (LPCVD) using Si2H6 gas at 470 °C and annealed at 600 °C in an N2 ambient for crystallization. The analysis using XRD and Raman scattering shows that crystalline nuclei are faster formed on the SiO2/Si than on the quartz, and the time needed for the complete crystallization of a-Si films on the SiO2/Si is greatly reduced to 8 h from ˜15 h on the quartz. In this study, it was first observed that crystallization in the a-Si deposited on the SiO2/Si starts from the interface between the a-Si film and the thermal oxide of the substrate, called interface-induced crystallization, while random nucleation process dominates on the quartz. The very smooth surface of the SiO2/Si substrate is responsible for the observed interface-induced crystallization of a-Si films.

Analytical Studies of the Capping Layer Effect on Aluminum Induced Crystallization of Amorphous Silicon

2006 ◽  
Vol 910 ◽  
Author(s):  
Husam Abu-Safe ◽  
Abul-Khair M. Sajjadul-Islam ◽  
Hameed A. Naseem ◽  
William D. Brown
Keyword(s):  
Amorphous Silicon ◽  
Layer Structure ◽  
Silicon Layer ◽  
Nodule Formation ◽  
Capping Layer ◽  
X Ray ◽  
Metal Induced Crystallization ◽  
Layer Effect ◽  
Polysilicon Films ◽  
Induced Crystallization

AbstractThe effect of capping layer on metal induced crystallization of amorphous silicon was studied. Three sets of samples were prepared in this study. All samples had the basic layer structure of amorphous silicon layer deposited on a glass substrate. This was followed by a thin aluminum layer deposition. The second and third sets, however, had a third layer of amorphous silicon with thicknesses of 20 and 50 nm, respectively. These layers were deposited on top of the aluminum. The samples were annealed at 400°C for 15, 30 and 45 minutes. The crystallization fraction in the resultant films was analyzed using X-Ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and atomic force microscopy. It was observed that the capping layer reduces nodule formation improving the smoothness of the crystallized polysilicon films.

Polysilicon Films Formed on Metal Sheets by Aluminium Induced Crystallization of Amorphous Silicon: Barrier Effect

2009 ◽  
Vol 1153 ◽  
Author(s):  
Prathap Pathi ◽  
Ozge Tüzün ◽  
Abdelilah Slaoui
Keyword(s):  
Amorphous Silicon ◽  
Electron Beam Evaporation ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coated Metal ◽  
Metal Sheets ◽  
Different Temperatures ◽  
Si Films ◽  
Induced Crystallization

AbstractPolycrystalline silicon (pc-Si) thin films have been synthesized by aluminium induced crystallization (AIC) of amorphous silicon (a-Si) at low temperatures (≤500°C) on flexible metallic substrates for the first time. Different diffusion barrier layers were used to prepare stress free pc-Si films as well as to evaluate the effective barrier against substrate impurity diffusion. The layers of aluminum (Al) and then amorphous silicon with the thickness of 0.27 μm and 0.37 μm were deposited on barrier coated metal sheets by means of an electron beam evaporation and PECVD, respectively. The bi-layers were annealed in a tube furnace at different temperatures (400-500°C) under nitrogen flow for different time periods (1-10hours). The degree of crystallinity of the as-grown layers was monitored by micro-Raman and reflectance spectroscopies. Structure, surface morphology and impurity analysis were carried out by X-ray diffraction, scanning electron microscopy (SEM) and EDAX, respectively. The X-ray diffraction measurements were used to determine the orientation of grains. The results show that the AIC films on metal sheets are polycrystalline and the grains oriented in (100) direction preferentially. However, the properties of AIC films are highly sensitive to the surface roughness.

Aluminum-Induced Crystallization of PECVD Amorphous Silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
Kenneth Jenq ◽  
Shawn S. Chang ◽  
Yaguang Lian ◽  
Grant Z. Pan ◽  
Yahya Rahmat-Samii
Keyword(s):  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Electron Beam Evaporation ◽  
Kinetics Analysis ◽  
Conventional Furnace ◽  
Through Diffusion ◽  
Induced Crystallization ◽  
Aluminum Induced Crystallization

ABSTRACTAluminum-induced crystallization (AIC) of amorphous silicon (a-Si) in a conventional furnace with N2 protection has been studied at reaction temperatures ranging from 200 to 500°C by using optical microscopy, and transmission and scanning electron microscopy. The a-Si and Al layers were deposited with plasma-enhanced chemical vapor deposition (PECVD) and electron beam evaporation, respectively. The structures in the study are Al/a-Si and a-Si/Al on Si or glass wafers coated with 3000 Å PECVD SiO2. It was found that Al induces crystallization of a-Si for both Al/a-Si and a-Si/Al structures by exchanging positions of Al and Si layer through diffusion of Si into Al and the grain size of crystallized Si (c-Si) increases with the decrease of AIC temperature. AIC for Al/a-Si structures starts at a temperature as low as 200°C, which is 100°C lower than that for a-Si/Al structures. Kinetics analysis found that the activation energies are 1.76 eV and 1.65 eV for both Al/a-Si and a-Si/Al structures, respectively. The quality of AIC c-Si depends on the order, thickness and thickness ratio of a-Si to Al. Microstructural observations indicated that the c-Si for Al/a-Si structures is better and more suitable for use in fabrication of thin film transistors (TFTs) than that for a-Si/Al structures.

Field-Assisted Germanium Induced Crystallization of Amorphous Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
J. Derakhshandeh ◽  
S. Mohajerzadeh ◽  
N. Golshani ◽  
E. Asl Soleimani ◽  
M.D. Robertson
Keyword(s):  
Electric Field ◽  
Amorphous Silicon ◽  
Applied Voltage ◽  
Crucial Role ◽  
Silicon Films ◽  
Electric Voltage ◽  
External Voltage ◽  
Annealing Conditions ◽  
Induced Crystallization

AbstractA field-assisted germanium-induced crystallization of amorphous silicon on glass is reported at temperatures below 500°C. Silicon films with a thickness of 0.1um are covered with 500Å of germanium as the seed of crystallization. Applying an electric field enhances the growth from both cathode and anode sides. XRD, SEM and TEM analyses have been used to study the crystallinity of the samples which have been treated under different annealing conditions, all confirming the polycrystalline nature of the annealed silicon films. The value of the applied voltage plays a crucial role in the crystalline quality of Si layers. While samples treated without an external voltage are not polycrystalline, an electric voltage of 10 V applied for a 1cm separation between anode and cathode, seems suitable for achieving good poly-crystalline Si layers. The size of grains varies between 0.1 and 0.2μm, as observed using SEM.

scholarly journals Large-Scale and Localized Laser Crystallization of Optically Thick Amorphous Silicon Films by Near-IR Femtosecond Pulses

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5296
Author(s):  
Kirill Bronnikov ◽  
Alexander Dostovalov ◽  
Artem Cherepakhin ◽  
Eugeny Mitsai ◽  
Alexander Nepomniaschiy ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Amorphous Silicon ◽  
Large Scale ◽  
High Surface ◽  
Femtosecond Laser Pulses ◽  
Visible Spectral Range ◽  
Ir Radiation ◽  
Near Ir ◽  
Si Films ◽  
Induced Crystallization

Amorphous silicon (α-Si) film present an inexpensive and promising material for optoelectronic and nanophotonic applications. Its basic optical and optoelectronic properties are known to be improved via phase transition from amorphous to polycrystalline phase. Infrared femtosecond laser radiation can be considered to be a promising nondestructive and facile way to drive uniform in-depth and lateral crystallization of α-Si films that are typically opaque in UV-visible spectral range. However, so far only a few studies reported on use of near-IR radiation for laser-induced crystallization of α-Si providing less information regarding optical properties of the resultant polycrystalline Si films demonstrating rather high surface roughness. The present work demonstrates efficient and gentle single-pass crystallization of α-Si films induced by their direct irradiation with near-IR femtosecond laser pulses coming at sub-MHz repetition rate. Comprehensive analysis of morphology and composition of laser-annealed films by atomic-force microscopy, optical, micro-Raman and energy-dispersive X-ray spectroscopy, as well as numerical modeling of optical spectra, confirmed efficient crystallization of α-Si and high-quality of the obtained films. Moreover, we highlight localized laser-induced crystallization of α-Si as a promising way for optical information encryption, anti-counterfeiting and fabrication of micro-optical elements.

EBSD analysis of polysilicon films formed by aluminium induced crystallization of amorphous silicon

2008 ◽  
Vol 516 (20) ◽  
pp. 6882-6887 ◽  
Author(s):  
Ö. Tüzün ◽  
J.M. Auger ◽  
I. Gordon ◽  
A. Focsa ◽  
P.C. Montgomery ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Ebsd Analysis ◽  
Polysilicon Films ◽  
Induced Crystallization
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