Activation Energy For Annealing Research Articles

Track annealing studies in glasses and minerals

An empirical formula relating annealing rate, V a, and activation energy of annealing, E a, is used to describe the annealing process in solid state nuclear track detectors and a three step annealing model is proposed. The activation energies for annealing are calculated and found that these vary from 0.16 eV to 1.0 eV for the detectors studied. It is observed that during thermal annealing of tracks, it is the annealing rate and not the activation energy which undergoes change with temperature.

Recombination-Enhanced Annealing of Gamma-Ray Induced Defects in GaAs1-xPx

The recombination-enhanced annealing of gamma-ray induced defects (electron traps) in GaAs1-xPx(x=0, 0.35 and 0.45) has been studied through the change in the defect density monitored by DLTS. A significant enhancement of the annealing rate is observed only under the minority carrier injection condition. It is found that a finite activation energy of 0.4–0.5 eV still remains even when the energy emitted in minority carrier capture at a defect is larger than the activation energy of pure thermal annealing.

Differential scanning calorimetry of heavy ion bombarded synthetic monazite

Abstract Specimens of synthetic monazite, CePO4, were rendered metamict by bombardment with 3 MeV Argon ions at fluences of 4 ions nm−2 or greater. Differential scanning calorimetry (DSC) was applied to the annealing of these specimens over a temperature range 550–720 K. The stored energy is shown to be 7.3±0.3 cal g1, independent of the fiuence from 4 to 10 ion nm−2. The activation energy of annealing of the damage is 2.7 ±0.3 eV and the temperature dependent rate constant is The application of DSC to the study of annealing of radiation damage in materials is discussed briefly. The saturation value of the stored energy with fiuence of 3 MeV Argon ions is compared to the approach to a saturation level observed in some glasses used to store radioactive wastes.

Thermal Annealing of Radiation Damage in CMOS ICs in the Temperature Range -140°C to +375°C

Annealing of radiation damage was investigated in the commercial,Z-and J-processes of the RCA CD4007A ICs in the temperature range from -140°C to +375°C. Tempering curves were analyzed for activation energies of thermal annealing, following irradiation at -140°C. It was found that at -140°C, the radiation-induced shifts in the threshold potentials were similar for all three processes. The radiation hardness of the Z-and J-processes is primarily due to rapid annealing of radiation damage at room temperature. In the region -140 to 20°C, no dopant-dependent charge trapping is seen, similar to that observed at higher temperatures. In the unbiased Z-process n-channels, after 1 MeV electron irradiation, considerable negative charge remains in the gate oxide.

The Effect of γ-Irradiation on Photoelectrical Properties of Sb–GaSe Structures

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Differential Scanning Calorimetry of Metamict Pu-Substituted Zirconolite

ABSTRACTSamples of CaPuTi2O7 were prepared by cold pressing and sintering. Plutonium was substituted for zirconium in order to characterize radiation damage effects. The energy stored in a sample which had reached saturation in swelling after storage at ambient temperature was measured with a differential scanning calorimeter. The total energy of 6.6±0.1 cal/g is released over the range 485–715° C. The activation energy of annealing of the damage is 1.22±0.05 eV. The temperature dependence of the rate constant is described by kT= 5.96E4 exp(−1.22/kBT) s−1 where kB and T are the Boltzmann's constant and temperature(K) respectively. A sample stored at 600°C was similarly evaluated and showed no release of stored energy to the precision of the apparatus (±0.1 cal/g). These results are applied to analysis of waste incorporation in Synroc and are correlated with analogous parameters for other materials.

Void coarsening during the annealing of neutron irradiated molybdenum

The annealing effect on the void swelling of neutron irradiated molybdenum is investigated in the present work. The behavior of voids during post-irradiation annealing is analyzed using a reaction rate equation. The best agreement of experimental results with the reaction rate equation is found when the reaction order is 2. This fact indicates that there is an interaction between voids during the post-irradiation annealing of molybdenum. Activation energy for void annealing is about 2.0 eV. From these results void migration or void coarsening by pipe diffusion of vacancies is discussed as the mechanism of void annealing.

Activation Energies of Thermal Annealing of Radiation-Induced Damage in n- and p-channels of CMOS Integrated Circuits, Part II

Tempering and isothermal curves of annealing of radiation damage in p- and n-channels of both commercial, or "soft," and radiation-hardened, or J-process, samples of RCA CD4007A CMOS integrated circuits, irradiated with both Co-60 gamma-rays and 1 MeV electrons, have been determined. These experimental data were analyzed for activation energies of thermal annealing using two theoretical treatments, one of which is a new approach proposed here. The resulting activation energy distribution of p-channels of both the commercial and J-process exhibit a single peak centered at about 1eV, whereas the distributions of n-channels of the commercial process exhibit two distinct peaks centered at about 0.9 and 1.2eV. The activation energy distributions of n-channels of the J-process show three peaks centered at about 0.7, 1.0 and 1.3eV. The two peaks in the n-channels of the commercial devices are attributed to the double diffusion of phosphorus and boron in the formation of the p-well and the subsequent growth of the gate oxide using this silicon surface. If this reasoning is correct, then it follows that the radiation-induced charge trapping in the gate oxide occurs mainly around the impurity centers. The n-channels of the J-process exhibit considerable reverse annealing under elevated temperatures and large long-term room-temperature annealing as compared to p-channels. No differences in the annealing modes between devices irradiated with Co-60 gamma rays and 1 MeV electrons were observed.

The kinetics of void annealing in neutron irradiated aluminum

The kinetics of void annealing in neutron-irradiated, high purity aluminum containing 0.006 void volume fraction was studied by means of dilatometry. Over the temperature range 358–573 K, the isothermal recovery of void volume fraction exhibited a logarithmic kinetic behavior. The data were analyzed in terms of a recovery rate equation of the form df dt = −fK 1 exp−[ Q 0−βf RT ] A theory for void annealing in irradiated aluminum is described based on the premise that voids shrinking under the action of interfacial forces emit single vacancies which migrate by diffusion to internal sinks where they are annihilated. In the theory, Q 0 is equal to the self diffusion activation energy. For the parameters Q 0 and K 1, satisfactory agreement between theory and experiment was achieved. The theory as presented cannot account for the parameter β. Its influence on recovery was speculated to be related to the damage state of the material. The ratio-of-slopes method was used to analyze recovery rate data from isochronal experiments. In common with the isothermal results, the measured activation energy for void annealing was found to be a function of how much void volume fraction remained to be annealed. An approximate void size distribution function was derived which agreed satisfactorily with experiment.

Activation Energies of Thermal Annealing of Radiation-Induced Damage in N- and P-Channels of CMOS Integrated Circuits

Tempering and isothermal curves of annealing of radiation damage in p- and n-channels of both commercial, or soft, and radiation-hardened, or J-process, samples of RCA CD4007A CMOS integrated circuits, irradiated with both Co-60 gamma-rays and 1 MeV electrons, have been determined. These experimental data were analyzed for activation energies of thermal annealing using two theoretical treatments, one of which is a new approach proposed here. The resulting activation energy distribution of p-channels of both the commercial and J-process exhibit a single peak centered at about 1eV, whereas the distributions of n-channels of the commercial process exhibit two distinct peaks centered at about 0.9 and 1.2eV. The activation energy distributions of n-channels of the J-process show three peaks centered at about 0.7, 1.0 and 1.3eV. The two peaks in the n-channels of the commercial devices are attributed to the double diffusion of phosphorus and boron in the formation of the p-well and the subsequent growth of the gate oxide using this silicon surface. If this reasoning is correct, then it follows that the radiation-induced charge trapping in the gate oxide occurs mainly around the impurity centers. The n-channels of the J-process exhibit considerable reverse annealing under elevated temperatures and large long-term room-temperature annealing as compared to p-channels. No differences in the annealing modes between devices irradiated with Co-60 gamma rays and 1 MeV electrons were observed.

Kinetics of defect cluster annealing in semiconductors

Abstract The change of the potential barrier height δω at the boundary of the matrix and defect clusters introduced by the high-energy particle irradiation in the course of isothermal annealing is analyzed. It is found, that δω is independent of the matrix doping level and is determined by the energy position of defect levels in the core and their concentrations only. The relations describing the change in δω during isothermal annealing of the defects in the core for the first- and the second-order reactions are obtained, allowing to determine the initial height of the potential barrier, the order of the reaction and the defect annealing activation energy in the core. On the basis of the results obtained the annealing of the defect clusters in GaAs has been analyzed.

Annealing kinetics of electron-irradiated GaAs heteroface solar cells in the range 175–200 °C

Annealing of electron-irradiation damage in GaAs solar cells is important for space applications. This paper describes studies conducted to understand this annealing process. GaAs heteroface solar cells were irradiated with 1×1015 1-MeV electrons/cm2 followed by thermal annealing. An activation energy for annealing of 1.25±0.14 eV and a frequency factor of (3.7±1.9) ×109 sec−1 were determined. A small component of the irradiation damage, which does not anneal measurably at 200 °C, was observed.

Track retaining properties of quartz for high temperature in-core neutron fluence measurements

Abstract Track registration and retention characteristics of natural quartz and its synthetic counterpart Vitreosil (fused silica) have been studied. Tests have been carried out at high temperatures (200–1000°C) and the detectors subjected to intense γ-ray fields of up to 250 MRads, with a view to establishing their suitability for high temperature in-core neutron fluence measurements. Both the major crystallographic axes of natural quartz reveal registration efficiencies of the order of unity showing little or no anisotropy when etched in boiling 65% NaOH, although superficial etching anisotropy of the track openings is highly evident. Whereas quartz shows residual tracks of fission fragments at ≃950°C, in both the major axes, tracks in vitreosil anneal out at 650°C. Annealing studies of the track ranges have not established preferential annealing relative to either axes, and the measurements of the reaction rates have yielded probable activation energies for annealing of 3.83 eV, and 0.85 eV for quartz and vitreosil respectively. Natural quartz can therefore be used as a neutron monitor in the extreme conditions of temperature and background radiation of the reactor core.

Observation of athermal defect annealing in GaP

Capacitance spectroscopy studies of lattice defects intentionally introduced into GaP diodes by 1-MeV electron irradiation have shown a very large enhancement in the defect annealing rate under conditions of e-h recombination. Six deep levels are observed and all exhibit recombination enhanced annealing. Four of the levels anneal athermally during recombination having the same rate at 100 K as at 300 K. Comparisons of the thermal annealing activation energy and the energy released during hole capture indicate that the observed athermal enhancement is a natural consequence of the wide GaP band gap.

A study of the layer and junction properties of boron implantation in silicon

Results of sheet conductivity and Hall effect measurements on boron implanted silicon samples are reported for both isothermal and isochronal annealing sequences. The activation energy of the implanted atoms was calculated and its dependence on implantation dose and substrate temperature during implantation is studied. From the behaviour of I/V characteristics during the annealing process, the location and activation energy associated with the quenching of the generation/recombination centres is derived.

Annealing of fission tracks in zircons

Etching conditions and thermal annealing effects have been studied for fission tracks in four kinds of zircons. The observation of fission tracks under an optical microscope was made with respect to the mean pit length as well as the mean pit density. Apparent rate constants were obtained by substituting the isochronal (60 minutes) annealing data into the ordinary equation of the rate constant. The order of reaction (almost 3rd or 4th) and the activation energy (1.7–2.9 eV) of annealing were determined from the Arrhenius plot of the apparent rate constants.

Atomic displacement effects on the cathodoluminescence of zinc selenide implanted with ytterbium ions

The cathodoluminescence emission spectrum of Yb 3+ in zinc selenide has been observed following ion implantation. The complexity of the resulting spectrum has been interpreted in terms of several distinct trigonally distorted lattice sites. The crystal field parameters obtained in this way indicate an appreciable degree of covalency between the rare-earth ions and the lattice. It has been found that all Yb 3+ spectra in zinc selenide are damagesensitive and the resulting effects can be interpreted on the assumption that the excitation mechanism is indirect, resonance transfer between like rare-earth ions is occurring and the concentration of centres is being changed. In turn, these concentration changes are used to determine a threshold energy of 8.0 eV (≡ 199 keV for the incident electron energy) for zinc displacement and an activation energy for thermal annealing of 0.14 + 0.01 eV, tentatively assigned to zinc interstitial motion.

Annealing Activation Energies of Sputtered Ge Films

Ge films were sputtered on water‐cooled substrates. Conductivity was measured during isothermal and step‐annealing experiments. These measurements indicate that activation energies for annealing increase from about 0.9–1.4 eV. A linear relationship was found between the activation energy for annealing and the change of conductivity at a certain reference temperature. The results are discussed and a mechanism is suggested in which a transformation from microcrystallinity to randomly disordered networks occurs in the low‐temperature annealing mode.

Optical and electrical properties of proton-bombarded p-type GaAs

The effect of 300-keV proton bombardment and subsequent annealing on the optical absorption and electrical resistivity of bulk p-type (p=2×1018 and 1.4×1019 cm−3) GaAs has been studied. Proton doses were in the range 1013−1017 cm−2. It is found that bombardment-induced optical absorption increases monotonically, but sublinearly, with proton dose. The shape of the optical transmission spectrum indicates that bombardment creates a distribution of energy levels extending into the forbidden gap. Activation energies for annealing of the optical absorption have been determined from isothermal annealing data and range from ∼1.5 to ∼3.4 eV, which indicates that at least two kinds of defects are involved. Current-voltage measurements show that the average electrical resistivity of the bombarded layers goes through a maximum at ∼2.5×105 Ω cm at a proton dose of ∼3×1015 cm−2. It is shown that annealing can eliminate the bombardment-induced optical absorption while still retaining a high electrical resistivity. The optimum annealing time and temperature is a function of the proton dose. From these results a set of useful conditions for the proton-bombardment fabrication of stripe-geometry GaAs lasers is determined. Many qualitative similarities exist between the results presented here and those obtained in GaP, which are presented in the following paper.

The effect of interstitial impurities on the annealing of neutron-irradiated vanadium

Annealing of neutron-irradiated vanadium was investigated in the temperature range 100–300°C using internal friction and resistivity measurements. The results indicate that the resistivity annealing stage at about 185°C is due to the migration of interstitial oxygen and carbon to radiation-produced defects, possibly small dislocation loops. This conclusion is based on the following evidence: 1. (1) The magnitude of the resistivity annealing stage was larger for vanadium with higher oxygen and carbon contents. 2. (2) The Snoek internal friction peak due to oxygen and carbon decreased upon post-irradiation annealing at 185°C by an amount consistent with the observed resistivity decrease. 3. (3) The resistivity decreased during post-irradiation annealing to below the pre-irradiation value. 4. (4) The activation energy for the resistivity annealing, 1.2 ± 0.1 eV, is the same as the activation energies for oxygen and carbon migration, 1.26 and 1.18 eV, respectively.