Suppression of Crystal Nucleation in Amorphous Si Thin Films by High Energy Ion Irradiation at Intermediate Temperatures

1990 ◽  
Vol 201 ◽  
Author(s):  
James S. Im ◽  
Jung H. Shin ◽  
Harry A. Atwater
Keyword(s):  
Ion Irradiation ◽  
High Energy ◽  
Intermediate Temperature ◽  
Crystal Nucleation ◽  
Potential Applications ◽  
Annealing Cycle ◽  
Amorphous Si ◽  
Si Films ◽  
Device Technology

AbstractIn situ electron microscopy has been used to observe crystal nucleation and growth in amorphous Si films. Results demonstrate that a repeated intermediate temperature ion irradiation/thermal annealing cycle can lead to suppression of nucleation in amorphous regions without inhibition of crystal growth of existing large crystals. Fundamentally, the experimental results indicate that the population of small crystal clusters near the critical cluster size is affected by intermediate temperature ion irradiation. Potential applications of the intermediate temperature irradiation/thermal anneal cycle to lateral solid epitaxy of Si and thin film device technology are discussed.

Suppression of Crystal Nucleation in Amorphous Si Thin Films by High Energy Ion Irradiation at Intermediate Temperatures

1990 ◽  
Vol 205 ◽  
Author(s):  
James S. Im ◽  
Jung H. Shin ◽  
Harry A. Atwater
Keyword(s):  
Ion Irradiation ◽  
High Energy ◽  
Intermediate Temperature ◽  
Crystal Nucleation ◽  
Potential Applications ◽  
Annealing Cycle ◽  
Amorphous Si ◽  
Si Films ◽  
Device Technology

AbstractIn situ electron microscopy has been used to observe crystal nucleation and growth in amorphous Si films. Results demonstrate that a repeated intermediate temperature ion irradiation/thermal annealing cycle can lead to suppression of nucleation in amorphous regions without inhibition of crystal growth of existing large crystals. Fundamentally, the experimental results indicate that the population of small crystal clusters near the critical cluster size is affected by intermediate temperature ion irradiation. Potential applications of the intermediate temperature irradiation/thermal anneal cycle to lateral solid epitaxy of Si and thin film device technology are discussed.

Crystal Nucleation in Amorphous Si Thin Films During Ion Irradiation

1990 ◽  
Vol 187 ◽  
Author(s):  
James S. Im ◽  
Harry A. Atwater
Keyword(s):  
Nucleation Rate ◽  
Ion Irradiation ◽  
High Energy ◽  
Crystal Nucleation ◽  
Transmission Electron ◽  
Crystal Transition ◽  
Amorphous Si ◽  
Si Films ◽  
Kinetics Of

AbstractThe nucleation and transformation kinetics of the amorphous-to-crystal transition in Si films under 1.5 MeV Xe+ irradiation have been investigated by means of in situ transmission electron microscopy in the temperature range T = 480–580°C. After an incubation period during which negligible nucleation occurs, a constant nucleation rate was observed in steady state, suggesting homogeneous nucleation. A significant enhancement in nucleation rate during high energy ion irradiation (6 orders of magnitude) was observed as compared with thermal crystallization, with an apparent activation energy of Qn = 3.9 ± 0.75 eV. Independent analyses of the temperature dependence of the incubation time, the crystal growth rate, and nucleation rate suggest that interface rearrangement kinetics and not the thermodynamic barrier to crystallization, are affected by ion irradiation.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

In-situ study of electrical transport in Pd/n-Si under high energy ion irradiation

2020 ◽  
Vol 35 (8) ◽  
pp. 085004
Author(s):  
Hemant K Chourasiya ◽  
Pawan Kumar Kulriya ◽  
Neeraj Panwar ◽  
Sandeep Kumar
Keyword(s):  
Electrical Transport ◽  
Ion Irradiation ◽  
High Energy ◽  
In Situ Study

Radiation-induced disordering and amorphization—An in situ HVEM study of uranium silicide with comparison to natural processes in zirconolite

1990 ◽  
Vol 48 (4) ◽  
pp. 534-535
Author(s):  
R. C. Birtcher ◽  
L. M. Wang ◽  
C. W. Allen ◽  
R. C. Ewing
Keyword(s):  
Electron Irradiation ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
In Situ Tem ◽  
In Situ Experiments

We present here results of in situ TEM diffraction observations of the response of U3Si and U3Si2 when subjected to 1 MeV electron irradiation or to 1.5 MeV Kr ion irradiation, and observations of damage occuring in natural zirconolite. High energy electron irradiation or energetic heavy ion irradiation were performed in situ at the HVEM-Tandem User Facility at Argonne National Laboratory. In this Facility, a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter have been interfaced to a 1.2 MeV AEI high voltage electron microscope. This allows a wide variety of in situ experiments to be performed with simultaneous ion irradiation and conventional transmission electron microscopy. During the electron irradiation, the electron beam was focused to a diameter of about 2 μ.m at the specimen thin area. The ion beam was approximately 2 mm in diameter and was uniform over the entire specimen. With the specimen mounted in a heating holder, the temperature increase indicated by the furnace thermocouple during the ion irradiation was typically 8 °K.

In-Situ Crystallization and Doping of a-Si Film by Means of Spin-On-Glass

1994 ◽  
Vol 345 ◽  
Author(s):  
Tomoyuki Sakoda ◽  
Chang-Dong Kim ◽  
Masakiyo Matsumura
Keyword(s):  
Laser Crystallization ◽  
Hole Conduction ◽  
Electron Field ◽  
In Situ Crystallization ◽  
Excimer Laser Crystallization ◽  
Doping Technique ◽  
Amorphous Si ◽  
Dopant Atoms ◽  
Si Films

AbstractA novel technique has been proposed for selective and in -situ excimer-laser crystallization and doping to thin poly-Si films. Dopant atoms are supplied, during the Si laser crystallization process, to the Si film on glass from the doped SOG (spin-on-glass) film coated on the top. Conductivity of the processed film was increased to more than 10S/cm from about 10−8S/cm of the starting film. This technique has been applied to the bottom gate amorphous-Si TFTs with self-aligned poly-Si source and drain. The electron field-effect mobility was 1.0cm2/Vs and the on/off current ratio was more than 106. No parasitic effects were observed, and the hole conduction was effectively. This in-situ crystallization and doping technique can also be applied to the top gate a-Si TFT process.

Ion Beam Induced Structural and Electrical Modifications in Crystalline and Amorphous Silicon

1993 ◽  
Vol 316 ◽  
Author(s):  
S. Coffa ◽  
A. Battaglia ◽  
F. Priolo
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Ion Irradiation ◽  
Deep Level ◽  
Ion Beam ◽  
Defect Structures ◽  
Transmission Electron ◽  
Defect Accumulation ◽  
Amorphous Si ◽  
Transient Spectroscopy

ABSTRACTThe mechanisms of defect accumulation and dynamic annealing in ion-implanted crystalline and amorphous Si are elucidated by performing conductivity and Raman spec-trascopy measurements in-situ during ion irradiation. In amorphous Si the entire gamut of defect structures has been characterized by analyzing the annealing kinetics from 77 K to ~ 800 K both during and after irradiation. Moreover the modifications in the electronic properties of crystalline Si produced by ion-irradiation have been investigated. The use of in-situ techniques in combination with transmission electron microscopy and deep-level transient spectroscopy allowed us to demonstrate the correlation between structural and electrical defects produced by ion-irradiation in Si.

scholarly journals Stability of Uranium Silicides During High Energy Ion Irradiation

1991 ◽  
Vol 235 ◽  
Author(s):  
R. C. Birtcher ◽  
L. M. Wang
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Amorphous State ◽  
Temperature Limit ◽  
High Energy ◽  
Grain Structure ◽  
Twin Structure ◽  
Fine Grain ◽  
Transmission Electron

ABSTRACTChanges induced by 1.5 MeV Kr ion irradiation of both U3Si and U3Si2 have been followed by in situ transmission electron microcopy. When irradiated at sufficiently low temperatures, both alloys transform from the crystalline to the amorphous state. When irradiated at temperatures above the temperature limit for ion-beam amorphization, both compounds disorder, with the Martensite twin structure in U3Si disappearing from view in TEM. Prolonged irradiation of the disordered crystalline phases results in nucleation of small crystallites within the initially large crystal grains. The new crystallites increase in number during continued irradiation until a fine grain structure is formed. Electron diffraction yields a powder-like diffraction pattern that indicates a random alignment of the small crystallites. During a second irradiation at lower temperatures, the small crystallizes retard amorphization. After 2 dpa at high temperatures, the amorphization dose is increased by over twenty times compared to that of initially unirradiated material.

scholarly journals Trim Simulations and Possible Studies for Edge-on Ion Irradiation of Electron Microscope Specimens

1992 ◽  
Vol 279 ◽  
Author(s):  
Loren J. Thompson ◽  
Charles W. Allen ◽  
Marcus C. Frischherz ◽  
Mauro P. Otero
Keyword(s):  
Electron Microscope ◽  
Ion Irradiation ◽  
Special Technique ◽  
Specimen Preparation ◽  
Plan View ◽  
Depth Direction ◽  
Transmission Electron ◽  
Si Films ◽  
Foil Specimen

ABSTRACTA TRIM code [1] has been modified to simulate a special technique, first described at the Spring 92 MRS Meeting [2], for in situ transmission electron microscope (TEM) experiments involving simultaneous ion irradiation, in which the resultant phenomena are observed as in a cross-section TEM specimen without further specimen preparation. Instead of ion-irradiating the film or foil specimen normal to the major surfaces and observing in plan view (i.e., in essentially the same direction), the specimen is irradiated edge-on (i.e., parallel to the major surfaces) and is observed normal to the depth direction of the irradiation. The results of calculations utilizing the modified TRIM code are presented for cases of 200 and 500 keV Co impinging onto the edge of Si films 200 and 600 nm thick. The limitations of the technique are discussed and the feasibility of experiments involving implantation of Co into Si and the formation of COSi2, which employ this technique, are briefly discussed.

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