Regrowth Rates of Amorphous Layers in Silicon-on-Sapphire Films

1985 ◽  
Vol 52 ◽  
Author(s):  
P. J. Timans ◽  
R. A. McMahon ◽  
H. Ahmed
Keyword(s):  
Refractive Index ◽  
Electron Beam ◽  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Amorphous Layer ◽  
Heating Cycle ◽  
Isothermal Heating ◽  
Time Resolved ◽  
Infra Red ◽  
High Absorption

ABSTRACTThe rate and direction of regrowth of amorphous layers, created by self-implantation, in silicon-on-sapphire (SOS) have been studied using time resolved reflectivity (TRR) experiments performed simultaneously at two wavelengths. Regrowth of an amorphous layer towards the surface was observed in specimens implanted with 3.1015Si+/cm2 at 50keV and regrowth of a buried amorphous layer, from a surface seed towards the sapphire, was observed in specimens implanted with 1.1015Si+/cm2 at 175keV. Rapid isothermal heating to regrow the layers was performed in an electron beam annealing system. The combination of 514.5nm and 632.8nm wavelengths was found to be particularly useful for TRR studies since the high absorption in amorphous silicon, at the shorter wavelength, means that the TRR trace is not complicated by reflection from the silicon-sapphire interface until regrowth is nearly complete. The dual wavelength method removes ambiguity about the position of the amorphous to crystalline interface and the direction of regrowth. The temperature dependence of the refractive index of silicon leads to large changes in the reflectivity of SOS films as they are heated. The combination of regrowth rate observations and reflectivity measurements during heating has been used to characterize the isothermal heating cycle, avoiding the difficulties of using pyrometers operating at the useful near infra-red wavelengths, where sapphire is transparent.

Epitaxial Explosive Crystallization of Amorphous Silicon Layers Buried in a Silicon (100) and (111) Matrix

1989 ◽  
Vol 147 ◽  
Author(s):  
P. A. Stolk ◽  
A. Polman ◽  
W. C. Sinke
Keyword(s):  
Amorphous Silicon ◽  
Cross Section ◽  
Ruby Laser ◽  
Crystallization Process ◽  
Amorphous Layer ◽  
High Density ◽  
Time Resolved ◽  
Explosive Crystallization ◽  
Amorphous Si ◽  
Twin Defects

Abstract420 nm thick amorphous Si layers buried in a Si (100) or Si (111) matrix, produced by 350 keV Si-implantation, were irradiated using a pulsed ruby laser. Time-resolved reflectivity measurements show that melting can be initiated buried in the samples at the crystalline-amorphous interface. Melting is immediately followed by explosive crystallization of the buried amorphous layer, which is started from the crystalline top layer. The velocity of this self-sustained crystallization process is determined to be 15.0 ± 0.5 m/s for Si (100) and 14.0 ± 0.5 m/s for Si (111). RBS and cross-section TEM reveal that epitaxially grown crystalline Si, containing a high density of twin defects, is formed in both the Si (100) and the Si (111) sample.

The measurement and analysis of epitaxial recrystallization kinetics in ion-beam-amorphized SrTiO3

1994 ◽  
Vol 9 (12) ◽  
pp. 3113-3120 ◽  
Author(s):  
J. Rankin ◽  
B.W. Sheldon ◽  
L.A. Boatner
Keyword(s):  
Refractive Index ◽  
Ion Beam ◽  
Amorphous Layer ◽  
Time Data ◽  
Time Resolved ◽  
Time Profiles ◽  
Epitaxial Regrowth ◽  
Measurement And Analysis ◽  
Kinetics Of ◽  
Good Agreement

The solid-state epitaxial-regrowth kinetics of ion-beam-amorphized SrTiO3 surfaces annealed in water-vapor-rich atmospheres have been studied using time-resolved reflectivity (TRR). For this material, the conversion of the reflectivity-versus-time data obtained from the TRR measurements to recrystallized depth-versus-time data is more complicated than in systems such as silicon, where the reflectivity can be fit by assuming that the refractive index N (N = n + ik) in the amorphous layer is constant. In SrTiO3, agreement between measurements made directly with Rutherford backscattering spectroscopy (RBS) and those made using TRR can be obtained only when N is permitted to vary within the amorphous layer, with nonzero values for both the real and imaginary components. In some cases, the roughness of the amorphous/crystalline interface must also be considered. Additionally, a model for H2O-enhanced epitaxial regrowth is presented, which is in good agreement with the shape of the depth-versus-time profiles that are obtained from the TRR data.

Melting of Ion Implanted and Relaxed Amorphous Silicon

1989 ◽  
Vol 157 ◽  
Author(s):  
M.G. Grimaldi ◽  
P. Baeri ◽  
G. Baratta
Keyword(s):  
Amorphous Silicon ◽  
Threshold Energy ◽  
Pulsed Laser ◽  
Amorphous Layer ◽  
Surface Melting ◽  
Time Resolved ◽  
The Difference ◽  
Pulsed Laser Irradiation ◽  
Ion Implanted

ABSTRACTThe difference in the melting temperature of ion implanted and relaxed amorphous silicon has been measured. Pulsed laser irradiation (λ=347 nm, τ=30 ns) has been used to induce surface melting in the amorphous layer and time resolved reflectivity to detect the melting onset. The threshold energy density for surface melting in the relaxed amorphous was found 15.9±.3% higher than that in the unrelaxed one. The estimate of the variation of the thermal parameters in amorphous silicon upon relaxation allowed a determination of ΔTM=45±10 K between relaxed and unrelaxed amorphous silicon.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Electron-beam damage of oxides at high current densities

1989 ◽  
Vol 47 ◽  
pp. 634-635
Author(s):  
M. R. McCartney ◽  
J. K. Weiss ◽  
David J. Smith
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Current Density ◽  
Transition Metal Oxides ◽  
Time Resolved ◽  
Rapid Acquisition ◽  
Resolution Electron ◽  
Current Densities ◽  
Electron Stimulated Desorption ◽  
Channel Analyzer

It is well-known that electron-beam irradiation within the electron microscope can induce a variety of surface reactions. In the particular case of maximally-valent transition-metal oxides (TMO), which are susceptible to electron-stimulated desorption (ESD) of oxygen, it is apparent that the final reduced product depends, amongst other things, upon the ionicity of the original oxide, the energy and current density of the incident electrons, and the residual microscope vacuum. For example, when TMO are irradiated in a high-resolution electron microscope (HREM) at current densities of 5-50 A/cm2, epitaxial layers of the monoxide phase are found. In contrast, when these oxides are exposed to the extreme current density probe of an EM equipped with a field emission gun (FEG), the irradiated area has been reported to develop either holes or regions almost completely depleted of oxygen. ’ In this paper, we describe the responses of three TMO (WO3, V2O5 and TiO2) when irradiated by the focussed probe of a Philips 400ST FEG TEM, also equipped with a Gatan 666 Parallel Electron Energy Loss Spectrometer (P-EELS). The multi-channel analyzer of the spectrometer was modified to take advantage of the extremely rapid acquisition capabilities of the P-EELS to obtain time-resolved spectra of the oxides during the irradiation period. After irradiation, the specimens were immediately removed to a JEM-4000EX HREM for imaging of the damaged regions.

XANES Registration by Electron Beam Position Scanning for Time-Resolved Experiment

1997 ◽  
Vol 7 (C2) ◽  
pp. C2-549-C2-552 ◽  
Author(s):  
S. G. Nikitenko ◽  
B. P. Tolochko ◽  
A. N. Aleshaev ◽  
G. N. Kulipanov ◽  
S. I. Mishnev
Keyword(s):  
Electron Beam ◽  
Time Resolved ◽  
Beam Position
Sign in / Sign up

Export Citation Format

Share Document