Direct Observation of Intermixing in GAAS/AIAS Multilayers After Very Low-Dose Ion-Implantation

1989 ◽  
Vol 157 ◽  
Author(s):  
M. Bode ◽  
A. Ourmazd ◽  
J.A. Rentschler ◽  
M. Hong ◽  
L.C. Feldman ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Monte Carlo ◽  
Ion Implantation ◽  
Monte Carlo Simulations ◽  
Low Dose ◽  
Atomic Plane ◽  
Lattice Imaging ◽  
Energetic Ions ◽  
Before And After ◽  
Composition Profiles

ABSTRACTWe combine chemical lattice imaging and digital vector pattern recognition to study quantitatively, kinetic intermixing in GaAs/AlAs multilayers. We thus obtain, with atomic plane resolution and near-atomic sensitivity, composition profiles across each interface of a multilayer stack before and after ion-implantation. Our results show significant intermixing even when only one 320 keV Ga+ ion is implanted at 77 K into each 2000 A2 area of the interface. This corresponds to an incident ion dose of 5×l012/cm2.The intermixing is not uniform along the interface. At each interface, we observe more intensely intermixed regions, whose widths correspond to those created by the damage track of a single implanted ion, as expected from Monte-Carlo simulations. It thus appears that we can directly image intermixing due to single energetic ions implanted into the multilayered GaAs/AlAs structure.

Diffusion in multilayers, studied by quantitative chemical mapping at the atomic level

1990 ◽  
Vol 48 (4) ◽  
pp. 354-355
Author(s):  
Y. Kim ◽  
A. Ourmazd
Keyword(s):  
Pattern Recognition ◽  
Atomic Plane ◽  
Quantitative Composition ◽  
Chemical Mapping ◽  
Lattice Image ◽  
Cross Sectional ◽  
Single Interface ◽  
Before And After ◽  
Lattice Images ◽  
Composition Profiles

Using chemical lattice imaging in combination with vector pattern recognition, we study diffusion and interdiffusion at single interfaces in mulilayered semiconductors quantitatively with atomic plane resolution. 20 periods of 50Å C-doped GaAs/50Å undoped GaAs/50Å Al0.4Ga0.6As grown by Molecular Beam Epitaxy(MBE) at 600C was examined to study interdiffusiuori across single GaAs/AlGaAs interfaces as a function of temperature (650C to 750C), depth of interface beneath the surface, and doping . After annealing in bulk form, cross-sectional TEM samples were prepared chemically. Chemical lattice images in the <100> zone axis obtained at an accelerating voltage of 400KV with a JEOL 4000-EX high resolution transmission electron microscope were analyzed by a digital pattern recognition method to obtain composition profiles at each interface before and after annealing.Figure 1 is a chemical lattice image of a C:GaAs/AlGaAs interface. The compositional information in the sample is contained in the local patterns that make up such images. The analysis of such chemical images by the pattern recognition yields quantitative composition profiles across single interfaces. The composition profiles shown in Figure 2 refer to a single interface at a depth of 300Å, before and after annealing at 700C for one hr.

A New Hafnium-Beryllium System Prioduced by Ion Implantation and Annealing Techniques

1983 ◽  
Vol 27 ◽  
Author(s):  
J.C. Soares ◽  
A.A. Melo ◽  
M.F. DA Silva ◽  
E.J. Alves ◽  
K. Freitag ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Single Crystals ◽  
Room Temperature ◽  
Low Dose ◽  
Correlation Method ◽  
High Dose ◽  
Tetrahedral Sites ◽  
Time Differential ◽  
Before And After ◽  
Beryllium Foil

ABSTRACTLow and high dose hafnium imolanted beryllium samoles have been prepared at room temperature by ion implantation of beryllium commercial foils and single crystals. These samples have been studied before and after annealing with the time differential perturbed angular correlation method (TDPAC) and with Rutherford backscattering and channeling techniques. A new metastable system has been discovered in TDPAC-measurements in a low dose hafnium implanted beryllium foil annealed at 500°C. Channeling measurements show that the hafnium atoms after annealing, are in the regular tetrahedral sites but dislocated from the previous position occupied after implantation. The formation of this system is connected with the redistribution of oxygen in a thin layer under the surface. This effect does not take place precisely at the same temperature in foils and in single crystals.

Channeling in 4H-SiC from an Application Point of View

2019 ◽  
Vol 963 ◽  
pp. 386-389 ◽  
Author(s):  
Peter Pichler ◽  
Tomasz Sledziewski ◽  
Volker Häublein ◽  
Anton Bauer ◽  
Tobias Erlbacher
Keyword(s):  
Monte Carlo ◽  
Ion Implantation ◽  
Monte Carlo Simulations ◽  
Electronic Devices ◽  
Point Of View ◽  
Power Electronic ◽  
Application Point ◽  
Doping Profiles

During ion implantation into monocrystalline semiconductors, some of the implanted atoms will be deflected to crystal directions along which they may penetrate deeply into the crystal. We investigate such channeling effects for Al and N implantation into 4H-SiC by Monte Carlo simulations. The focus of the work is on the effects of channeling on doping profiles, the relevance for the net doping of typical power electronic devices, and the influence of scattering oxides.

scholarly journals Off-lattice pattern recognition scheme for kinetic Monte Carlo simulations

2012 ◽  
Vol 231 (9) ◽  
pp. 3548-3560 ◽  
Author(s):  
Giridhar Nandipati ◽  
Abdelkader Kara ◽  
Syed Islamuddin Shah ◽  
Talat S. Rahman
Keyword(s):  
Pattern Recognition ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Kinetic Monte Carlo ◽  
Kinetic Monte Carlo Simulations ◽  
Lattice Pattern

Investigation on Wet Etching 4H-SiC Damaged by Ion Implantation

2017 ◽  
Vol 897 ◽  
pp. 367-370
Author(s):  
Sophie Guillemin ◽  
Romain Esteve ◽  
Christian Heidorn ◽  
Gerald Unegg ◽  
Gerald Reinwald ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Ion Implantation ◽  
Monte Carlo Simulations ◽  
Wet Etching ◽  
Etching Solution ◽  
Experimental Findings ◽  
Wet Etch ◽  
Ion Implanted

In this work investigation on wet etching of ion implanted 4H-SiC has been performed. Starting with the search for a suitable etching solution is followed by investigations on how to damage 4H-SiC in an efficient way involving different implantation species in various doses. With the help of Monte Carlo simulations a model for the experimental findings is proposed to derive the limitations for the wet etch capability.

Monte Carlo simulations for ion implantation.

Hyomen Kagaku ◽  
1990 ◽  
Vol 11 (10) ◽  
pp. 591-597
Author(s):  
Tohru ISHITANI
Keyword(s):  
Monte Carlo ◽  
Ion Implantation ◽  
Monte Carlo Simulations

scholarly journals Extended pattern recognition scheme for self-learning kinetic Monte Carlo simulations

2012 ◽  
Vol 24 (35) ◽  
pp. 354004 ◽  
Author(s):  
Syed Islamuddin Shah ◽  
Giridhar Nandipati ◽  
Abdelkader Kara ◽  
Talat S Rahman
Keyword(s):  
Pattern Recognition ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Kinetic Monte Carlo ◽  
Kinetic Monte Carlo Simulations ◽  
Self Learning

PROSPECTIVE VALIDATION OF A MODEL-BASED DOSING REGIMEN FOR AMIKACIN IN NEONATES: FEASIBLE AND RELEVANT

2015 ◽  
Vol 101 (1) ◽  
pp. e1.40-e1
Author(s):  
Anne Smits ◽  
Roosmarijn De Cock ◽  
Karel Allegaert ◽  
Sophie Vanhaesebrouck ◽  
Meindert Danhof ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Dosing Regimen ◽  
Model Based ◽  
Prediction Distribution ◽  
Before And After ◽  
Almost All ◽  
Trough Levels

IntroductionA neonatal amikacin dosing regimen was previously developed based on a population pharmacokinetic model. The aim of the current study was to prospectively validate this model-derived dosing regimen.MethodsFirst, early (before and after second dose) therapeutic drug monitoring (TDM) observations were evaluated for achieving target trough (<3 mg/L) and peak (>24 mg/L) levels. Secondly, observed concentrations were compared with model-predicted concentrations, whereby the results of an NPDE (normalized prediction distribution error) were considered as well. Subsequently, Monte Carlo simulations were performed. Finally, remaining causes limiting amikacin predictability (prescription errors and disease characteristics of outliers) were explored.ResultsIn 579 neonates [median (range) birth bodyweight 2285 (420–4850) g, postnatal age 2 (1–30) days, gestational age 34 (24–41) weeks], 90.5% of early peak levels reached 24 mg/L and 60.2% of trough levels was <3 mg/L (93.4% ≤5 mg/L). Observations were accurately predicted by the model without bias, which was confirmed by the NPDE. Monte Carlo simulations showed that peak concentrations >24 mg/L were reached in almost all patients. Trough values <3 mg/L were documented in 78–100% and 45–96% of simulated cases, respectively, when ibuprofen was co-administered or not. Suboptimal trough levels were found in patient subgroups with postnatal age <14 days and current weight >2000g.ConclusionsProspective validation of a model-based neonatal amikacin dosing regimen resulted in optimized peak and trough concentrations in almost all patients. Adapted dosing for patients with suboptimal trough levels was proposed. Besides improving dosing individualization, feasibility and relevance of neonatal prospective validation studies was demonstrated.

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