摘要:

The ESRPbcenter has been observed in thermally oxidized single‐crystal silicon wafers, and compared with oxide fixed chargeQssand oxidation‐induced interface statesNst. ThePbcenter is found to be located near the interface on (111) wafers. Itsganisotropy is very similar to that of known bulk silicon defects having SiIIIbonded to three other Si atoms; thePbunpaired electron orbital, however, is exclusively oriented normal to the (111) surface. ThePbcenter cannot be identified with any other known defect in Si or SiO2; in particular, it is totally unlike the commonE′ center of SiO2. In contrast toQss, bothPbandNstwere found to be greatly reduced by steam oxidation and hydrogen annealing. BothPbandNstmay be regenerated by subsequentN2anneals at 500 °C. In a graded series of samples,PbandNstare found to be proportional and nearly equal in concentration. This possible confirmation of SiIIIat the interface, and correlation withNst, support the theoretical indication of an SiIIIband‐gap energy level. TheE′ center is unobservable, and if present, exists only in a concentration well below that ofQss. Thus, in addition to a lack of strong correlation withPb,Qssis evidently not due toE′ centers in their normal charge state. Overall, ESR is judged to be a useful technique for research on silicon wafer defects.

ISSN:0021-8979    

DOI:10.1063/1.326732

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Solid phase reactions in the temperature range between 250 and 600 °C between Si and V‐Pd bilayers as well as alloy layers have been studied by MeV4He+backscattering and x‐ray diffraction techniques. When a Pd layer is interposed between Si and V, the bilayer system starts to react at <300 °C with the formation of Pd2Si. Annealing at higher temperatures (∼600 °C) leads to a uniform layer of VSi2formed on top of the Pd2Si. Reversing the bilayer sequence (Si/V/Pd) raises the reaction temperature of the system to ∼500 °C with V mixing into the Pd layer. Annealing at higher temperature leads to the formation and accumulation of Pd2Si at the interface and a mixed (nonuniform) structure of Pd2Si and VSi2in the outer surface region. For a Pd‐rich alloy (Pd80V20), a reaction started at about 300 °C and produced Pd2Si by depleting Pd from the alloy. This resulted in a mixed structure of Pd2Si and VSi2in the outer region, similar to the final stage of the Si/V/Pd system. For a V‐rich alloy (Pd90V10), the formation temperature of Pd2Si is raised to ∼500 °C and again leads to a mixed structure. The amount of accumulation of Pd2Si at the substrate‐silicide interface increases with the Pd content in the alloy.

ISSN:0021-8979    

DOI:10.1063/1.326733

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The detection characteristics of point‐contact W‐Ni diodes at 10 MHz, 9.5 GHz, and 28.3 THz are investigated as a function of diode resistance (contact pressure). The experimental results are compared with predictions from tunneling theory taking into account circuit parameters. Good agreement is obtained when the relaxation behavior of the metallic whisker antenna is considered at infrared wavelengths.

ISSN:0021-8979    

DOI:10.1063/1.326734

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The generation lifetime, capture cross section, and thermal emission rates for the gold acceptor level in bulk silicon have been studied using MOS techniques. The experimental methods used were the pulsed high‐frequency capacitance‐time and nonequilibrium linear‐voltage‐ramp techiniques at various temperatures. By correlating the results of the above measurements, the capture cross section &sgr; and trap energyEtof the gold acceptor state were determined as a function of temperature in the range 235–265 °K. It was observed that &sgr; increases with increasing temperature and has a value of the order of 1.0×10−15cm2. On the other hand, the trap energyEtwas found to decrease with increasing temperature, suggesting that it varies in unison with the silicon energy gap. Finally, from the above results the thermal emission ratesenandepwere determined, with the assumption that the degeneracy factor andgA=1. For the temperature range investigated, the ratioen/epvaried from 30 at 235 °K to 20 at 265 °K.

ISSN:0021-8979    

DOI:10.1063/1.326735

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The basic theory and design of a reciprocating magnetic refrigerator to pump heat from 2.2 to 4.2 K is presented. The results of initial experiments are shown. These results include conduction losses, eddy current losses, frictional losses, and mixing losses. Two cooling cycles were attempted and a net cooling power of 52 mW was observed at 1/60 Hz. The key problems in this design are identified and discussed.

ISSN:0021-8979    

DOI:10.1063/1.326683

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A method for determining the magnetic anisotropy profile of an ion‐implanted garnet layer is presented. To do this the eigenvalue equation for spin waves is solved numerically for a system consisting of a very thick film with uniform perpendicular anisotropy and a surface layer in which the anisotropy varies through the surface. Results of this calculation are matched to experimental FMR data from samples cut from the same wafer but etched by different amounts. A measurement of the exchange constant in the implanted layer may be possible if two or more surface modes are visible. The anisotropy profiles of samples implanted with 2×1014Ne+/cm2at 50, 100, and 150 keV were reconstructed in this manner. The profile was found to show a broad peak centered at a depth somewhat shallower than the projection range for Ne+at the appropriate energy. The value of the change in anisotropy was shown to match that predicted from a magnetostrictive origin and the measured change in lattice constant in the surface layer. The measured exchange constants in the implanted layer were 1.1×10−7and 1.7×10−7ergs/cm for 100‐ and 150‐keV implanted samples, respectively.

ISSN:0021-8979    

DOI:10.1063/1.326684

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We report on Brillouin‐scattering measurements of thermally excited acoustic‐surface phonons, and bulk and surface magnons, in sputtered films of Fe1−xBxand Co1−xBx. From the slope of the surface‐magnon frequency shift with field we determinegfactors of 2.09±0.03 for Fe1−xBxand 2.16±0.03 for Co1−xBx, with no significant trend as a function of composition and no difference between amorphous and polycrystalline materials. The magnetization for pure Fe and Co agree with literature values. The magnetization of sputtered and quenched materials of the same composition are in agreement provided both samples are amorphous. Effective exchange corrections of orderDk2=0.1–0.5 kOe (whereDis the spin‐wave stiffness andkis a magnon‐wave vector) are needed to properly fit the dependence of bulk‐magnon frequency shift on field. The magnetization values determined with such fits agree within experimental error with magnetizations obtained from the surface magnons. Possible origins of theDk2correction are discussed. In films below about 200 nm in thickness, structure is observed in the bulk‐magnon peaks which may be due to standing spin waves. The potential of Brillouin scattering as a tool for thin‐film characterization is discussed.

ISSN:0021-8979    

DOI:10.1063/1.326685

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We report on Brillouin‐scattering measurements of thermally excited surface acoustic phonons, and bulk and surface magnons, in quenched ribbons of ferromagnetic metallic glasses with compositions Fe100−xBx(x=14–28), Fe76Mo4B20, FexNi80−xB20(x=20–60), and Co75−xFexSi15B10(x=0–6). Room‐temperature surface‐phonon velocity is found to increase monotonically with increasing B in FeB, and with increasing Fe in FeNiB. The velocity is almost 10% less in Fe76Mo4B20than in Fe80B20. The phonon velocity is not field dependent, even in compositions where large &Dgr;Eeffects occur. Thegfactor, determined from the slope of surface‐magnon frequency with field, is 2.09±0.02 for Fe100−xBx. The intensity of surface‐ and bulk‐magnon scattering is independent of magnetostriction in CoFeSiB.

ISSN:0021-8979    

DOI:10.1063/1.326686

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The addition of a small amount of rhodium to thin films of Permalloy substantially improves resistance to atmospheric corrosion with a relatively small degradation of magnetic properties. X‐ray photoemission spectroscopy data shows that rhodium, in contrast to chromium, does not change valence during corrosion of these nickel‐iron alloys, nor is it enriched at the alloy surface.

ISSN:0021-8979    

DOI:10.1063/1.326687

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Ga‐substituted magnetic garnet films are laser annealed with annealing times of several milliseconds by scanning a cw argon laser beam across the film. Locally the bubble collapse field and the saturation magnetization increase, and the domain width decreases permanently unless conventional furnace annealing is used to restore the material to its initial state. We attribute the observed effects to a crystallographic site redistribution of the Ga and the Fe atoms in annealed regions which support mobile bubbles. The site distribution is changed from a state quenched in from the growth temperature to a higher‐temperature state representative of the laser‐annealing treatment. The effect does not involve melting.

ISSN:0021-8979    

DOI:10.1063/1.326688

出版商:AIP    

年代:1979

数据来源: AIP