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.

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.

Nucleation And Growth Rates in Isothermal Crystallization Op Amorphous Si50Ge50 Films

1993 ◽  
Vol 321 ◽  
Author(s):  
J. H. Song ◽  
James S. Im
Keyword(s):  
Growth Rate ◽  
Nucleation Rate ◽  
Growth Rates ◽  
Isothermal Crystallization ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Two Dimensional ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Si Films

ABSTRACTIsothermal crystallization behavior of as-deposited thin amorphous Si50Ge50 films (∼1000Å-thick) at 580°C has been investigated using transmission electron Microscopy (TEM). The crystal counting method was employed in order to obtain directly the two-dimensional steady-state crystal nucleation rate of 3.9×103 #/cm2sec (equivalent volumetric nucleation rate of 3.4×108 #/cm3sec). The Modified two-dimensional Johnson-Mehl-Avrami analysis, in which the growth rate of the crystals was the only adjustable parameter, and in which the time-dependent nucleation rate and the size effect associated with the onset of the observation are considered, was developed in order to extract the crystal growth rate of 16.5 Å/sec. When compared to the crystallization of a-Si films, these nucleation and growth rates confirm the observation that it is possible to achieve significantly faster crystallization at lower temperatures while producing substantially better Microstructures (i.e., > 5 μ grain-sized poly-Si50Ge50 obtained within two hours at 580°C vs. 1–2Μm grain-sized poly-Si obtained in about > 10 hours at 600°C).

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.

Crystal Nucleation in Amorphous Si Films on Glass Substrate by Si+ Ion Implantation

1991 ◽  
Vol 230 ◽  
Author(s):  
Tomonori Yamaoka ◽  
Keiji Oyoshi ◽  
Takashi Tagami ◽  
Yasunori Arima ◽  
Shuhei Tanaka
Keyword(s):  
Ion Implantation ◽  
Glass Substrate ◽  
Ion Beam ◽  
Crystal Nucleation ◽  
Projected Range ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
Amorphous Si ◽  
Si Films ◽  
Almost All

AbstractCrystallization of amorphous Si films on a glass substrate using Si+ ion implantation is investigated. 100keV and 180keV Si+ ion implantations into 600nm-thick amorphous Si layers crystallize half and almost all of the film thicknesses, respectively. This result demonstrates that crystallization by ion implantation, which contains both crystal nucleation and grain growth, is due to ion-solid interaction, and not to “pure” thermal effect by ion beam heating. Furthermore, two distinct regions are observed in transmission electron microscopy investigation of grain size at different depths of crystallized Si/SiO2 multi-layer specimens. The deep region below the projected range is composed of grains smaller than in the shallow region. This result is strongly related with crystal nucleation and growth kinetics by ion implantation.

Lateral Solid Phase Epitaxy of Evaporated Amorphous Si Films onto SiO2 Patterns

1983 ◽  
Vol 25 ◽  
Author(s):  
H. Yamamoto ◽  
H. Ishiwara ◽  
S. Furukawa ◽  
M. Tamura ◽  
T. Tokuyama
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Implantation ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Si Substrates ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Si Films ◽  
Kinetics Of

ABSTRACTLateral solid phase epitaxy (L-SPE) of amorphous Si (a-Si) films vacuum-evaporated on Si substrates with SiO2 patterns has been investigated, in which the film first grows vertically in the regions directly contacted to the Si substrates and then grows laterally onto SiO2 patterns. It has been found from transmission electron microscopy and Nomarski optical microscopy that use of dense a-Si films, which are formed by evaporation on heated substrates and subsequent amorphization by Si+ ion implantation, is essentially important for L-SPE. The maximum L-SPE length of 5–6μm was obtained along the <010> direction after 10hourannealing at 600°C. The kinetics of the L-SPE growth has also been investigated.

Dopant Diffusion and Grain Growth in Arsenic-Implanted Poly-Si

1987 ◽  
Vol 106 ◽  
Author(s):  
L. R. Zheng ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Amorphous Layer ◽  
Crystal Nucleation ◽  
Initial Size ◽  
Diffusion Behavior ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Si Films

ABSTRACTThe diffusion behavior of arsenic and the grain growth of Si in arsenic doped poly-Si were investigated by MeV4 He2+ backscattering techniques and transmission electron microscopy. By implanting arsenic ions into poly-Si films the surface portion was made amorphous and crystallized upon annealing. In-situ mssurements showed crystal nucleation and growth at temperatures of 650 – 700° C with a dimension comparable to the thickness of the amorphous layer. Annealing at temperatures up to 850°C increased the number of the large grains, but the average grain size did not change significantly. In the unimplanted region grains retained their initial size until 885°C, although implanted arsenic was found to diffuse into this region along grain boundaries. At 885°C penetration of arsenic into the interior of grains caused significant grain growth. We also found that single implants of boron somewhat increased grain size, whereas boron codoped with arsenic appeared to reduce the effect of arsenic doping. These observations support the hypothesis that the enhanced growth rate and the electrical activity of Si near the grain boundary are closely interrelated.

Growth of near noble metal Pd and Pt thin film silicides morphology and structure

1984 ◽  
Vol 42 ◽  
pp. 498-499
Author(s):  
E. I. Alessandrini ◽  
M. O. Aboelfotoh
Keyword(s):  
Noble Metals ◽  
Annealing Temperature ◽  
Chemical Compounds ◽  
Barrier Properties ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Stable Chemical ◽  
Metal Thickness ◽  
Amorphous Si ◽  
Si Films

Considerable interest has been generated in solid state reactions between thin films of near noble metals and silicon. These metals deposited on Si form numerous stable chemical compounds at low temperatures and have found applications as Schottky barrier contacts to silicon in VLSI devices. Since the very first phase that nucleates in contact with Si determines the barrier properties, the purpose of our study was to investigate the silicide formation of the near noble metals, Pd and Pt, at very thin thickness of the metal films on amorphous silicon.Films of Pd and Pt in the thickness range of 0.5nm to 20nm were made by room temperature evaporation on 40nm thick amorphous Si films, which were first deposited on 30nm thick amorphous Si3N4 membranes in a window configuration. The deposition rate was 0.1 to 0.5nm/sec and the pressure during deposition was 3 x 10 -7 Torr. The samples were annealed at temperatures in the range from 200° to 650°C in a furnace with helium purified by hot (950°C) Ti particles. Transmission electron microscopy and diffraction techniques were used to evaluate changes in structure and morphology of the phases formed as a function of metal thickness and annealing temperature.

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