摘要:

Phase formation at temperatures well below the melting point of the phases was studied in thin silicon–near‐noble‐metal films by means of4He+ion‐backscattering spectrometry and x‐ray diffractometry in SiO2/Si/Mfilm systems, where the metal‐film thickness was larger than that of the Si film. In the initial stage of compound formation where both unreacted Si andMlayers are present, theM2Si phase has been found. At increasing annealing times and temperatures, more and more metal‐rich phases have been detected. The Si‐Ni thin‐film system evolution follows exactly the phase diagram reported in the literature; moreover, for Ni, Pt, and Pd‐Si thin‐film interactions the end phases are dictated by the phase equilibrium and can be predicted by the phase diagrams.

ISSN:0021-8979    

DOI:10.1063/1.325626

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An amorphous to a polycrystal or a single‐crystal transition by ruby‐laser irradiation of amorphous Si, obtained through ion implantation, is discussed. Both free‐generation andQ‐switched laser mode operation are used. Under a free‐generation operation only the amorphous to polycrystal transition is obtained, which is attributed to nonthermal effects. In theQ‐switched mode both transitions are obtained. The single‐crystal transition is interpreted as due mainly to the melting of the amorphous layer.

ISSN:0021-8979    

DOI:10.1063/1.325709

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The mechanism of the interaction of polycrystalline Ag‐Al thin‐film couples to form Ag2Al at temperatures from 107 to 221 °C has been studied. Techniques of film characterization included Rutherford backscattering, x‐ray diffraction, and SEM. The dependence of the interaction on the grain size of the Ag film (660–7500 A˚) was measured. An effective activation energy of 0.86±0.05 eV was found. The reaction is believed to occur initially by nucleation and growth of Ag2Al grains at Ag grain boundaries at the interface; after formation of a continuous Ag2Al layer, the growth of this layer follows at1/2law, controlled by diffusion through the grain boundaries of the Ag2Al layer.

ISSN:0021-8979    

DOI:10.1063/1.325710

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Helium permeability, diffusivity, and solubility have been measured for sodium, potassium, rubidium, and cesium germanate glasses, and for one series of sodium‐potassium germanate glasses. In each case, the helium permeability and diffusivity exhibit minima in the property‐composition curves. These minima shift to greater alkali oxide content and increase in magnitude in the order Cs, Rb, K, Na‐K, Na. These minima result from corresponding maxima in activation energy for helium migration. Helium solubilities do not exhibit similar minima, but rather decrease monotonically with increasing alkali oxide content. These results appear to be related to free‐volume changes in the glasses as a function of composition. The inability of the current structural model for these glasses to explain the results of the present study raises questions regarding the validity of that model.

ISSN:0021-8979    

DOI:10.1063/1.325655

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The diffusion of phosphorus from a thick epitaxial layer into a silicon substrate has been investigated using the spreading‐resistance technique. By comparing the diffusion profile under a free oxidized surface with the profile under a masked surface, it has been shown that surface oxidation enhances diffusion at low temperatures and retards diffusion at high temperatures. The conditions which favor enhanced diffusion are those under which stacking faults grow; retarded diffusion is associated with stacking‐fault shrinkage. Enhanced diffusion is due to the oxide injecting excess interstitials into the substrate; retarded diffusion is caused by vacancy injection. It is concluded that phosphorus diffuses by the interstitialcy mechanism and that the criterion for interstitial or vacancy injection is the relative value of the anion and cation fluxes across the oxide‐silicon interface.

ISSN:0021-8979    

DOI:10.1063/1.325656

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Correlation effects which arise during self‐diffusion are normally associated with a tracer‐defect mechanism. It is not widely appreciated that diffusive mechanisms, which are not normally considered to be correlated, may become so as a consequence of crystal contamination. Two examples are given to illustrate the establishment of diffusive correlations by solute element contamination. The examples are interstitial diffusion in a dilute fcc ternary alloy and vacancy migration in a dilute binary fcc alloy.

ISSN:0021-8979    

DOI:10.1063/1.325657

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The steady‐state and transient electrical properties of a material containing one or two species of mobile charge carrier in contact with blocking electrodes are examined. The systems treated are 2, 20, and 40 Debye lengths in extent and exemplify the transition from thin‐film or membranelike behavior to the more usual case in which well‐defined space‐charge layers form at each electrode. The static capacitance of the electrode/material/electrode system is examined and the response of the system to a step‐function applied potential difference is obtained by numerical simulation. The simulation results show clearly the role of the system length and charge carrier mobilities in determining the system response. The decay of total current following the potential step is numerically fitted to a sum of exponential decays. The nonlinear character of system response becomes apparent when the transient current associated with the formation of space‐charge layers in response to a potential step is compared with that which accompanies the decay of the space‐charge layers following the sudden restoration of zero potential difference between the electrodes. The redistribution of charge carriers and the electrostatic potential both in the steady state and at representative times during the transient response are presented and discussed.

ISSN:0021-8979    

DOI:10.1063/1.325658

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Evaporated two‐layered thin films of Pd‐Ni, Pt‐Ni, and Pt‐Pd on single‐crystal Si have been vacuum annealed in the temperature range 200–900 °C. The sequence of films as well as substrate orientation have been varied. The silicide formation has been studied by MeV He+backscattering spectrometry and glancing angle x‐ray diffraction. The silicide layers are highly inhomogeneous in the elemental depth distribution for annealing below 600 °C. Above 700 °C, the distributions become homogeneous. The silicide‐substrate interface shows varying sharpness depending upon substrate orientation and evaporation sequence. We suggest the existence of ternary monosilicides of the type Pt1−xPdxSi, Pt1−xNixSi, and Pd1−xNixSi. The Pt1−xPdxSi ternary silicide is stable up to 900 °C; the others are not.

ISSN:0021-8979    

DOI:10.1063/1.325659

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Carbon vapor obtained by vaporization of graphite is diluted into argon. Its subsequent condensation into solid particles is studied. The particle diameter is determined as a function of argon and carbon partial pressures and of the distance to the carbon source. A mechanism involving irreversible associations of colliding particles is proposed.

ISSN:0021-8979    

DOI:10.1063/1.325660

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Electron microprobe and helium ion backscattering are used to measure the stoichiometry of rf‐sputtered SiO2films at a precision of ?1%. Both oxygen‐excess and oxygen‐deficient films occur. Optical absorption and electron spin resonance characterize atomic defects in the films. The correlation between stoichiometry and atomic defects is poor. The reproducibility of composition and of atomic defects from run to run, when sputtering conditions are held constant, is good.

ISSN:0021-8979    

DOI:10.1063/1.325662

出版商:AIP    

年代:1979

数据来源: AIP