摘要:

In high‐dose ion implantation for materials modification, the maximum concentration of the implanted species is determined by ion‐induced erosion (sputtering) of the implanted layer. In this review, we consider the influence of preferential sputtering and atomic mixing. The maximum concentration of the implanted species is given roughly byr/Sand extends over a depthWwhereSis the sputtering yield,ris the preferential sputtering factor (1/2≲r≲2) andWis a depth comparable to the ion range. Good agreement between calculation and experiment is found for 150‐keV Au implanted into Cu or Fe. Surface conditions, such as oxide layers or carbon films, can alter sputtering yields and can lead to the mixing of surface contaminants throughout the implanted layer. Implantation of speciesAinto a target materialABresults in a different concentration limit, but again preferential sputtering and the total sputtering yield set this limit. Calculations for PtSi indicate that the concentration of Si is decreased by implantation of Si forS≳3.

ISSN:0022-5355    

DOI:10.1116/1.569820

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

摘要:

Implantation into metals at room and lower temperatures can result in the formation of metastable phases. For low concentrations, ≲1 at. %, substitutional and interstitial solutions have been observed for implantation into Be, Fe, Ni, and Cu. At higher concentrations, ≳10 at. %, both metastable solid solutions and amorphous alloys have been formed in Fe, Ni, and Cu.

ISSN:0022-5355    

DOI:10.1116/1.569821

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

摘要:

Amorphous metals lack the long‐range atomic periodicity typically found in crystalline materials and their atomic arrangements are usually best described in terms of the random packing of hard spheres. Recent work has demonstrated that ion implantation can produce metastable, amorphous alloys. A brief review of the structure of noncrystalline metals is presented and recent data on ion‐implanted amorphous alloys is reviewed. A discussion of the route by which ion‐induced amorphization proceeds is also given together with some future prospects.

ISSN:0022-5355    

DOI:10.1116/1.569822

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

摘要:

Thermally activated processes cause ion‐implanted metals to evolve from the initial state toward thermodynamic equilibrium. The degree of this equilibration is strongly dependent upon temperature, and is considered here for three temperature regimes which are distinguished by the varying mobilities of interstitial and substitutional atoms. In addition, perturbations resulting from the irradiation environment are discussed. Examples are given of the use of implanted and annealed alloys in studies of diffusion, phase diagrams, and solute trapping.

ISSN:0022-5355    

DOI:10.1116/1.569823

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

摘要:

In this review, we emphasize three aspects of the regrowth of ion‐implanted amorphous Si layers: (1) orientation dependence of the regrowth kinetics, (2) impurity effects on the regrowth kinetics, and (3) impurity distribution due to regrowth. To account for the orientation dependence there are at least three proposed models: (1) geometric model, (2) stress relaxant model, and (3) surface reconstruction model. Each of these models is discussed here. For amorphous Ge regrowth, the characteristics are similar to those of Si. Parallels are drawn whenever possible. An example is given to illustrate the use of ion‐implanted‐regrowth process to modify the crystallinity of thin layers.

ISSN:0022-5355    

DOI:10.1116/1.569824

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

ISSN:0022-5355    

DOI:10.1116/1.569825

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

摘要:

The objective of this review is to illustrate with some selected topics the advances made by ion implantation in modifying semiconductor materials, particularly silicon. The progress in obtaining extremely shallow impurity distributions, either by direct implants or by recoil methods, has led not only to better insights into the stopping phenomena of energetic particles in the low‐energy range, but also to the capability of developing advanced Schottky barrier diodes. The application of radiation damage for gettering purposes is discussed in combination with the marked increase in the pipe‐limited yield of bipolar devices. Another topic related to the generation of defects during implantation is the radiation‐enhanced diffusion. Recent studies and advances in the understanding of these phenomena are presented.

ISSN:0022-5355    

DOI:10.1116/1.569826

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

摘要:

Ion implantation has become an important part of magnetic bubble technology. The damage produced by implantation places the implanted layer in a state of in‐plane compression. This can change the easy axis of magnetization from perpendicular to parallel to the surface in a material having a negative magnetostriction coefficient. Several magnetic effects result from the creation of a thin layer of in‐plane magnetization at the top of the magnetic bubble supporting material. These include flux capping of the bubbles, control of the allowable magnetic bubble states, formation of bubble guiding rails at the boundaries of implanted areas, and creation of a moving magnetic pole pattern for bubble propagation in an external rotating in‐plane magnetic field. Other observed effects include increases in lattice parameter up to ∠2% and enhancement of the etching rate of the material by as much as a factor of 1000. Implantation is now widely used to suppress hard bubbles, and there is the possibility that ion implantation will be used to produce the drive patterns of the next generation of high‐density magnetic bubble memories.

ISSN:0022-5355    

DOI:10.1116/1.569827

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

摘要:

The temperature dependence of electron spin polarization and intensity in low‐energy electron diffraction (LEED) from a clean W(001) surface has been measured over the range 1000°–300°C. The effect of temperature on polarization is found to be greatest at energies for which the intensity is low and the polarization, and rate of change of polarization with energy, is large. The present results may be interpreted in terms of a shift of polarization features toward lower energies as a result of thermal expansion when the crystal is heated.

ISSN:0022-5355    

DOI:10.1116/1.569828

出版商:American Vacuum Society    

年代:1978

数据来源: AIP

摘要:

Auger electron spectroscopy (AES) studies of theMNNspectra of MoO3, MoO2, oxidized Mo foil, and Mo (100) single crystal reveal the splitting of the Auger transition peaks which involve valence electrons. The splitting of these transition peaks is attributed to the altered valence‐band density of states which illustrates the existence of two major oxidation states in the specimen. The additional state is caused either through surface oxidation or beam‐induced reduction. Based on theM4,5N2,3Vtransition peak, the measurement shows the chemical shift to be 5 eV for Mo6+and 1 eV for Mo4+. The reduction of the oxygen Auger peak‐to‐peak height (APPH) with a simultaneous enhancement of the Mo APPH and sample coloration change in the beam‐irradiated area has been observed during electron bombardment of oxide specimens. The observable changes indicate the occurence of beam‐induced decomposition and the preferential loss of oxygen from the surface. The electron bombardment mainly causes the reduction of MoO3to MoO2. The efficiency of further reduction to the elemental metal state is low as compared to the reduction process from Mo6+to Mo4+. Comparison of predicted Auger intensities, based on the contribution to the total Auger intensity from each atomic plane, with the experimental observations confirms the formation of a Mo4+‐rich surface layer on a beam‐irradiated specimen.

ISSN:0022-5355    

DOI:10.1116/1.569829

出版商:American Vacuum Society    

年代:1978

数据来源: AIP