摘要:

The quantum theory of widening of the electron transverse energy levels at axial channeling because of the processes of elastic scattering from oscillating crystal nuclei is developed. It is shown that the periodicity of atoms along an axis leads to rather strong suppression of transition probabilities between the transverse energy levels of the discrete and continuous spectrum.

ISSN:0033-7579    

DOI:10.1080/00337578308217820

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A method for the numerical solution of integr-differential equations governing the parameters of ion implantation and energy deposition distributions is described. The influence of the choice of elastic scattering cross-section approximation on the results of damage and ionization distribution calculations is shown. A comparison with some experimental data and Brice's calculations is carried out. The applicability of the Pearson IV distribution function for the construction of the damage profiles is demonstrated.

ISSN:0033-7579    

DOI:10.1080/00337578308217821

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The dose dependences of the structure state in (111) and (001)-Si wafers were studied by transmission electron diffraction and electron microscopy techniques after argon, nitrogen and oxygen ion implantation and high temperature annealing. The critical doses for forming twins and polycrystalline layers, which depend on the orientation, were shown to be attained for all types of ions. The critical dose values increase in the succession Ar, N, O. A model which relates the observed phenomena to the chemical nature of the implanted impurity and explains the structure differences of the implantation layers at high impurity concentrations is presented.

ISSN:0033-7579    

DOI:10.1080/00337578308217822

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Germanium <100><110>, and >111< single crystals implanted with 46 keV Te ions with doses between 1012and 1015ions cm−2have been analyzed by TEM of surface replicas, RHEED, and MeV He+channelling. The combination of these types of measurements reveals the effect of crystalline orientation on heavy ion damage in a germanium lattice. The degree of disorder in the bulk, resulting from low dose implantation is lowest at <110> and >111< channelling and highest at <100> channelling.

ISSN:0033-7579    

DOI:10.1080/00337578308217823

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The technique of cross-sectional transmission electron microscopy (TEM) has been applied to study the nature of extended defects in proton bombarded GaAs as a function of dose and post-bombardment anneal. For low doses (up to 5 × 1015protons cm−2) the main defects were found to be Frank dislocation loops which develop after an anneal at 500°C. In high dose (1017protons cm−2) samples damage of a diffuse structure was detectable by TEM without annealing. Upon annealing, dislocation networks interspersed with voids became visible. Models for the growth of voids and Frank loops with temperature of anneal have been developed and the experimental details analysed accordingly. From these analyses an average enthalpy for vacancy migration of 0.3 eV is deduced for GaAs.

ISSN:0033-7579    

DOI:10.1080/00337578308217824

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Energy loss and straggling for protons, deuterons and α-particles in thin gold foils were measured by the indirect transmission technique. The measured stopping powers of the hydrogen ions agree reasonably well with the semi-empirical values of Andersen and Ziegler. The measured stopping powers for the helium ions are between 4% and 12% higher than the semi-empirical values of Ziegler. Stopping ratios of the He and hydrogen ions for the same target foils are slightly higher than Ziegler's master curve. The straggling values are energy independent above 0.4 MeV/amu. The hydrogen values are about 20 % lower than the Bohr estimate, while the straggling of the helium ions tend to reach the Bohr value at energies above 0.4 MeV/amu.

ISSN:0033-7579    

DOI:10.1080/00337578308217825

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The damage produced by pulsed electron beam irradiation of vanadium single crystals has been studied by the channeling technique and by thin film X-ray analysis. A surface disorder peak and a small dechanneling component was produced by applying electron energy densities below the melting threshold. The structure of the surface disorder was microcrystalline or amorphous and the dechanneling component could be described by small angle boundaries. After melting of the crystal surface to a depth of approximately 2 μm, epitaxial regrowth with a high defect density took place.

ISSN:0033-7579    

DOI:10.1080/00337578308217826

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Interaction of neutral beams (γ-quanta, neutrons, etc.) with atomic planes and rows is considered. Reflection of beams from these atomic systems is also considered. A possibility of space redistribution of such particles within the channel and possibility of turning them by a bent crystal is shown.

ISSN:0033-7579    

DOI:10.1080/00337578308217827

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Using the TDPAC-technique after ion implantation of181Hf into Pt, a defect, trapped at the181Hf probe atoms after annealing at 630 K-850 K, could be identified as a carbon impurity atom. Measurements in a Pt single crystal showed a <110>-symmetry axis of the associated axially symmetric electric field gradient with a preferred direction almost parallel to the normal vector of the crystal surface. This leads to the conclusion that single carbon atoms are trapped on regular lattice sites next to the Hf probe and a strong interaction of these Hf-C complexes either with the collision cascades produced during the Hf implantations or the crystal surface must be assumed.

ISSN:0033-7579    

DOI:10.1080/00337578308217828

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337578308217829

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor