Defects and Diffusion in Si+ Implanted GaAs

1993 ◽  
Vol 300 ◽  
Author(s):  
K.S. Jones ◽  
H.G. Robinson ◽  
T.E. Haynes ◽  
M.D. Deal ◽  
C.C. Lee ◽  
...  
Keyword(s):  
Dislocation Loop ◽  
Vacancy Concentration ◽  
Total Concentration ◽  
Time Interval ◽  
Type I ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Extrinsic Dislocation ◽  
Area Of Concern ◽  
And Diffusion

ABSTRACTThe effect of extended defects on the diffusion of ion implanted species is an area of concern in the development of process simulators for GaAs. This study explores the effect of type I extended defects including voids and dislocation loops on the diffusion of Si implanted into GaAs. <100> Semi-insulating GaAs wafers were implanted with 1 × 1014/cm2 Si+ at implant temperatures between -51°C and 80°C and at energies ranging from 20 keV to 200 keV. SIMS results show that the diffusivity of Si decreases with both increasing implant temperature and increasing implant energy. At the same time extrinsic dislocation loop concentrations also increased. For the implant conditions studied, no voids were observed. The diffusion results can only be reconciled with the TEM results if the dislocation loops are behaving in a reactive rather than proactive manner. In other words, the changes in vacancy concentration that are affecting the diffusivity are also affecting the loop concentration. This model is supported by evidence that Si diffusivity is enhanced over the same time interval the dislocation loops are dissolving which is consistent with the loops having a reactive role. It remains unclear whether the existence of loops significantly affects the total concentration of vacancies and thus diffusion by acting as a competing sink.

Extended Defects in Fe-Implanted InP After Thermal Annealing

1993 ◽  
Vol 316 ◽  
Author(s):  
C. Frigeri ◽  
C. Bocchi ◽  
A. Carnera ◽  
A. Gasparotto ◽  
N. Gambacorti ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Stacking Fault ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Near Surface ◽  
Sample Stacking ◽  
Stacking Fault Tetrahedra ◽  
Crystalline Substrate ◽  
Extrinsic Dislocation ◽  
Recrystallization Front

ABSTRACTThe recovery of the implant-induced damage and the defects present after thermal annealing at 650 °C in Fe-implanted InP have been investigated by TEM, RBS and X-ray diffractometry as a function of the annealing time that was varied betweeen 0.5 and 2 h. The near-surface damaged layer was removed only for annealing times ≥ 1.5 h. The annealed samples contained stacking fault tetrahedra of vacancy type, extrinsic dislocation loops and microdefects. These extended defects were mostly localized in a band corresponding to the region of transition between amorphous top layer and crystalline substrate as was detected in the as-implanted sample. Stacking fault tetrahedra and loops have also been observed before and beyond this band, respectively. Such defects could be due to either shear strains at the recrystallization front or implant-induced point defects.

scholarly journals FACTORS INVOLVED IN THE PRODUCTION OF IMMUNITY WITH PNEUMOCOCCUS VACCINE

1928 ◽  
Vol 48 (1) ◽  
pp. 83-104 ◽  
Author(s):  
Alvan L. Barach ◽  
Keyword(s):  
Intact Cell ◽  
Broth Culture ◽  
Time Interval ◽  
Type I ◽  
Type Ii ◽  
Lobar Pneumonia ◽  
The Common ◽  
Immunity Mechanism ◽  
Lethal Doses ◽  
Pneumococcus Type

1. The antigenic function of a pneumococcus vaccine made from the intact cell was compared with that derived fron a watery extract of the cell free from formed elements. In each instance, the immunity produced was dependent upon type-specific protective substance and not upon the elaboration of the common protein antibody. 2. The vaccine made from the intact cell resulted in both active and passive immunity which began on the 3rd day, increased markedly to the 5th, and remained approximately stationery to the 7th day. In the case of the Berkefeld filtrate of the shaken bacteria and the filtrate of the broth culture, the immunity began on the 4th day, increased to the 5th, and remained approximately stationery to the 7th day. The immunity produced by Pneumococcus Type I vaccine is greater than that produced by Type II. On the 3rd day, mice vaccinated with Type I vaccine resisted 100,000 minimal lethal doses, whereas mice immunized with Type II resisted 10,000 minimal lethal doses. On the 5th day, a larger percentage of mice survived these doses than on the 3rd day. 3. Certain factors related to the preparation and dosage of the vaccine are discussed. 4. As far as the time interval and the degree of immunity produced are concerned, these results suggest the possibility of employing pneumococcus vaccine in suitable doses in the treatment of lobar pneumonia. That an earlier activity of the immunity mechanism could actually be initiated in a patient with lobar pneumonia has still to be demonstrated.

Collagenous Materials Enhance Healing of Chronic Skin Ulcers

1987 ◽  
Vol 110 ◽  
Author(s):  
Frederick H. Silver ◽  
Charles J. Doillon ◽  
Blas Rojo ◽  
Robert M. Olson ◽  
Chandrakala Y. Kamath ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Systemic Infection ◽  
Collagen Sponge ◽  
Time Interval ◽  
Type I ◽  
Wound Area ◽  
Skin Ulcers ◽  
Chronic Skin ◽  
Observation Period

AbstractType I collagen in a porous sponge form attracts fibroblasts in culture and accelerates repair of animal wounds. This study examines the effect of type I collagen sponge and flakes on healing of chronic skin ulcers. Patients included in this study had skin ulcers.Patients included in this study had skin ulcers characterized by loss of dermis and epidermis without exposure of muscle, tendon or bone. Patients showing evidence of systemic infection or patients with ulcers that decreased in area during an initial three week observation period were excluded.Three out of seven patients treated with a collagen sponge and twelve out of fourteen patients treated with collagen flakes showed a 40% decrease in wound area after six weeks of treatment. In comparison, eighteen control patients showed no change in wound area over the same time interval. These results suggest that collagen flakes are effective in initiating healing of chronic skin ulcers.

The Electrical and Optical Properties of Point and Extended Defects in Silicon Arising from Oxygen Precipitation

2007 ◽  
Vol 131-133 ◽  
pp. 225-232 ◽  
Author(s):  
R. Jones
Keyword(s):  
Optical Properties ◽  
Electrical Properties ◽  
Electrical Activity ◽  
Theoretical Work ◽  
Precipitation Process ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Electrical And Optical Properties ◽  
Oxygen Precipitation ◽  
Oxygen Atoms

Oxygen precipitation in Si is a complex set of processes which has been studied over many years. Here we review theoretical work relating to the precipitation process. At temperatures around 450°C oxygen atoms become mobile and form a family of thermal double donors. The structure of these defects and the origin of their electrical activity is discussed. At temperature around 650°C these donors disappear and there is a growth of SiO2 precipitates along with rod like defects which are extended defects involving Si interstitials. At higher temperatures these collapse into dislocation loops. The structure and electrical properties of the rod like defect are described and compared with those of dislocations.

Impact of Industry Conditions on Innovation

2018 ◽  
pp. 278-303 ◽  
Author(s):  
J. Roland Ortt ◽  
Tineke Mirjam Egyedi
Keyword(s):  
High Tech ◽  
Time Interval ◽  
Development Phase ◽  
Product Innovations ◽  
High Tech Product ◽  
Successive Time Interval ◽  
Standards And Regulations ◽  
Innovation And Diffusion ◽  
And Diffusion ◽  
Adaptation Phase

This chapter underscores the importance of timing by focusing on the effect of pre-existing standards and regulations on the innovation and diffusion of new high-tech product innovations. The effect is assessed in terms of the time interval between the invention of a technological principle and the introduction of the first marketable product (development phase), and the successive time interval up to the start of large-scale industrial production and diffusion (adaptation phase). Fifty heterogeneous cases of new high-tech product innovations from 1850 onward are analysed. Results indicate that pre-existing standards and regulations significantly shorten the adaptation phase, an effect not found for the development phase. The shortening effect on the adaptation phase is particularly evident for more radical innovations and for innovations that are more interrelated with a larger technological system. This accelerating effect on the diffusion of innovations is highly relevant for innovation managers and policy makers alike.

scholarly journals Microstructure Evolution in ZrCx with Different Stoichiometries Irradiated by Four MeV Au Ions

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3768
Author(s):  
Boxin Wei ◽  
Dong Wang ◽  
Yujin Wang ◽  
Haibin Zhang
Keyword(s):  
Radiation Damage ◽  
Microstructure Evolution ◽  
Vacancy Concentration ◽  
Ion Beam ◽  
Grazing Incidence ◽  
Dislocation Loops ◽  
Black Dot ◽  
X Ray Diffraction ◽  
Near Surface ◽  
Transmission Electron

ZrCx ceramics with different stoichiometries were irradiated under a four MeV Au ion beam in doses of 2 × 1016 ions/cm2 at room temperature, corresponding to ~130 dpa. Grazing incidence, X-ray diffraction and transmission electron microscopy were performed to study the radiation damage and microstructure evolution in ZrCx ceramics. With the decrease in C/Zr ratio, the expansion of ZrCx lattice became smaller after irradiation. Some long dislocation lines formed at the near-surface, while, in the area with the greatest damage (depth of ~400 nm), large amounts of dislocation loops formed in ZrC, ZrC0.9 and ZrC0.8. With the increase in carbon vacancy concentration, the size of the dislocation loops gradually decreased. Few dislocation loops were found in ZrC0.7 after irradiation, and only black-dot defects were found in the area with the greatest damage. For the non-stoichiometric ZrCx, with the increase of the intrinsic vacancies, the number of C interstitials caused by irradiation decreased, and the recombination barrier of C Frenkel pairs reduced. The above factors will reduce the total number of C interstitials after cascade cooling, suppressing the formation and growth of dislocation loops, which is significant for the enhancement of the tolerance of radiation damage.

scholarly journals Molecular Simulation of the Adsorption and Diffusion in Cylindrical Nanopores: Effect of Shape and Fluid–Solid Interactions

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 608 ◽  
Author(s):  
Harry Cárdenas ◽  
Erich Müller
Keyword(s):  
Decisive Role ◽  
Molecular Shape ◽  
Type I ◽  
Surface Strength ◽  
Bulk Fluid ◽  
Self Diffusion ◽  
Interaction Sites ◽  
Adsorbed Phase ◽  
Dynamics Simulations ◽  
And Diffusion

We report on molecular simulations of model fluids composed of three tangentially bonded Lennard-Jones interaction sites with three distinct morphologies: a flexible “pearl-necklace” chain, a rigid “stiff” linear configuration, and an equilateral rigid triangular ring. The adsorption of these three models in cylindrical pores of diameters 1, 2, and 3 nm and with varying solid–fluid strength was determined by direct molecular dynamics simulations, where a sample pore was placed in contact with a bulk fluid. Adsorption isotherms of Type I, V, and H1 were obtained depending on the choice of pore size and solid–fluid strength. Additionally, the bulk-phase equilibria, the nematic order parameter of the adsorbed phase, and the self-diffusion coefficient in the direction of the pore axis were examined. It was found that both the molecular shape and the surface attractions play a decisive role in the shape of the adsorption isotherm. In general, the ring molecules showed a larger adsorption, while the fully flexible model showed the smallest adsorption. Morphology and surface strength were found to have a lesser effect on the diffusion of the molecules. An exceptional high adsorption and diffusion, suggesting an enhanced permeability, was observed for the linear stiff molecules in ultraconfinement, which was ascribed to a phase transition of the adsorbed fluid into a nematic liquid crystal.

Defects In Erbium/Oxygen Implanted Silicon

1996 ◽  
Vol 442 ◽  
Author(s):  
X. Duan ◽  
J. Palm ◽  
B. Zheng ◽  
M. Morse ◽  
J. Michel ◽  
...  
Keyword(s):  
Habit Plane ◽  
Dislocation Loop ◽  
Systematic Study ◽  
Sharp Contrast ◽  
Dislocation Loops ◽  
Different Temperatures ◽  
Free Material ◽  
Habit Planes

AbstractA systematic study of defects in the Er/O implanted silicon was conducted using TEM, HRTEM and SIMS. Defect-free material was obtained after the annealing of 400 keV Er+ implanted (100)Si. In sharp contrast, several forms of secondary defects consisting of dislocations, dislocation loops and precipitates were induced upon annealing at different temperatures in the 4.5 MeV implanted (100)Si sample. The isothermal evolution of the defects and reactions between dopants and defects were studied. Oxygen tends to segregate into the dislocation loop zones, where platelet precipitates with habit planes of {111} were found. Following dissociation of oxygen and erbium, plate-like Er precipitates were generated, which are most likely ErSi2 with a habit plane of {111}

Workspace Analysis and Visualization of Mechanical Manipulators With Non-Unilateral Constraints

2005 ◽  
Author(s):  
Jingzhou Yang ◽  
Karim Abdel-Malek
Keyword(s):  
Null Space ◽  
Domain Boundary ◽  
Mathematical Formulation ◽  
Time Interval ◽  
Perturbation Approach ◽  
Type I ◽  
Type Ii ◽  
Unilateral Constraints ◽  
Kinematic Chains ◽  
Type Iii

An analytical method is presented to obtain all surfaces enveloping the workspace of a general n degree-of-freedom mechanism with non-unilateral constraints. The method is applicable to kinematic chains that can be modeled using the Denavit-Hartenberg representation method for serial manipulators. The method introduced in this paper is based upon analytical criteria for determining singular behavior of the mechanism. A perturbation approach is implemented to determine the interior and exterior of the workspace. The complete mathematical formulation is presented and illustrated using 3 and 4 DOF spatial manipulators. The paper present a rigorous analysis of the sub-Jacobians to determine a classification of singularities: Type I sets are position Jacobian singularities; Type II sets are instantaneous singularities that are due to a generalized joint that is reaching its apex; Type III sets are domain boundary singularities, which are associated with the initial and final values of the time interval; Type IV sets are coupled singularities, which are associated with a relative singular Jacobian, where the null space is reduced in one submatrix due to either of two occurrences: a Type II or Type III singularities. The paper presents a general formulation for determining the workspace.

Geochemical characterization of hydrocarbon source rocks of the Triassic-Jurassic time interval in the Mandawa basin, southern Tanzania: Implications for petroleum generation potential

2020 ◽  
Vol 123 (4) ◽  
pp. 587-596
Author(s):  
A. Emanuel ◽  
C.H. Kasanzu ◽  
M. Kagya
Keyword(s):  
Source Rocks ◽  
Geochemical Data ◽  
Time Interval ◽  
Type I ◽  
Hydrocarbon Generation ◽  
Type Ii ◽  
Geochemical Characterization ◽  
Type Iii ◽  
Petroleum Generation

Abstract Triassic to mid-Jurassic core samples of the Mandawa basin, southern Tanzania (western coast of the Indian Ocean), were geochemically analyzed in order to constrain source rock potentials and petroleum generation prospects of different stratigraphic formations within the coastal basin complex. The samples were collected from the Mihambia, Mbuo and Nondwa Formations in the basin. Geochemical characterization of source rocks intersected in exploration wells drilled between 503 to 4042 m below surface yielded highly variable organic matter contents (TOC) rated between fair and very good potential source rocks (0.5 to 8.7 wt%; mean ca. 2.3 wt%). Based on bulk geochemical data obtained in this study, the Mandawa source rocks are mainly Type I, Type II, Type III, mixed Types II/III and Type IV kerogens, with a predominance of Type II, Type III and mixed Type II/III. Based on pyrolysis data (Tmax 417 to 473oC; PI = 0.02 to 0.47; highly variable HI = 13 to 1 000 mg/gTOC; OI = 16 to 225 mg/g; and VR values of between 0.24 to 0.95% Ro) we suggest that the Triassic Mbuo Formation and possibly the mid-Jurassic Mihambia Formation have a higher potential for hydrocarbon generation than the Nondwa Formation as they are relatively thermally mature.

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