摘要:

The thermoelectric power (TEP) of structurally characterized Cu‐based dilute alloy films containing 1, 2, and 5 at.&percent; Al, Ge, or Sn has been studied in the temperature range 80–350 K. The TEP of alloy films increases with thickness to reach a saturation value at ≳2800 A˚. The addition of impurities reduces the magnitude of the TEP of copper films while its sign remains positive. The temperature dependence of the TEP is affected markedly by the presence of impurities. Structural disorder, impurity, and phonon‐drag contributions to the TEP have been separated by using the Nordheim‐Gorter relation. Contribution of the Fermi‐surface distortions (and thus change in the neck radius of the Fermi surface) to the TEP has been estimated.

ISSN:0021-8979    

DOI:10.1063/1.325167

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Mobile ions in SiO2layers of MOS structures have been investigated with the thermally stimulated ionic current (TSIC) method. Two distinct peaks were observed in the temperature range 30–350 °C, the first at about 150 °C and the second at about 300 °C. Measurements on samples intentionally contaminated with either sodium or potassium show that the first peak is due to the motion of sodium ions, whereas the second peak results from the motion of potassium ions. The surface‐trapping model describes the curves well when a Gaussian spread in activation energy is assumed. When a physically plausible value for the emission time constant is assumed (10−12s), an activation energy is found that is consistent with an emission‐limited process.

ISSN:0021-8979    

DOI:10.1063/1.325168

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A thermally stimulated surface potential (TSSP) method has been developed to estimate the parameters of the insulator‐semiconductor interface in MIS structures. As TSSP is measured in the open‐circuit condition, charge on the gate electrode and voltage applied across the insulating layer are both constant in the measurement. For the above reasons, the analysis of TSSP is simplified, and theoretical TSSP curves can be calculated under non‐steady‐state and steady‐state conditions. The samples used for our experiments are Al‐SiO2‐Si MIS structures. To estimate the energy distribution of interface states, the temperature‐vs‐potential characteristic is used, particularly the point where the interface changes from non‐steady‐state to steady state. The characteristic can be clearly and easily obtained by a convenient method devised in the present work. The total amount of interface states, their energy distribution, and their lifetime are estimated in a wide energy range from the characteristic by simple calculation. Further, the relaxation mechanisms of the interface are discussed for samples having substrates of bothp‐ andn‐type Si.

ISSN:0021-8979    

DOI:10.1063/1.325169

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A new mathematical approach for the influence of mobile positive ions on the current‐voltage characteristics of MOS structures is presented. This new method gives formulations which are more applicable than those described in the literature. Examples of the application of these formulations are presented.

ISSN:0021-8979    

DOI:10.1063/1.325170

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

An investigation has been carried out in order to explore means to improve the stability of the in‐line Josephson‐tunneling gates, which are fabricated using Pb films containing In and/or Au additions as electrodes. The investigation has revealed that incorporation of several modifications in a previously reported gate‐fabrication process results in at least a fourfold increase in the stability during thermal cycling from 298 to 4.2 °K. For a total of 38 gates fabricated using the modified process, only about 30&percent; were found to have failed after 500 cycles. In comparison, the same percentage failure was observed after only 120 cycles, even for the most stable set of 19 gates which were fabricated using the previous method. Evaluation of the results indicates that the observed improvement in the stability could be attributed to the use of reduced electrode film thicknesses and an alteration of the base‐electrode fabrication process. In this paper the process modifications which resulted in the improved stability and corresponding junction characteristics and cycling data are described.

ISSN:0021-8979    

DOI:10.1063/1.325171

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Amorphous thin films of NdxCo1−xand NdxFe1−xalloys were prepared over the compositional range 0.08⩽x⩽0.71 by e‐beam evaporation. Magnetization and anisotropy of the samples were studied over a wide temperature range with the aid of a force balance magnetometer, Hall effect measurements, and Mo¨ssbauer spectroscopy. It was found that the magnetization of the alloys could not be accounted for by a completely collinear alignment (ferromagnetic) of the Nd and transition‐metal subnetworks. Mean field analysis of the magnetization data showed a large reduction of the Nd–transition‐metal exchange coupling as compared to their Gd analogs. A model was developed which requires that Nd be dispersed in a cone whose axis is parallel to that of the transition‐metal subnetwork by strong coupling to randomly oriented local crystal field axes. This dispersion reduces the Nd net moment to 77&percent; of its free‐ion moment in NdxCo1−xalloys and to 25&percent; of its free‐ion moment in NdxFe1−xalloys. There is evidence that some dispersion also occurs in the Fe subnetwork. Anisotropy in NdxCo1−xalloys was found to be proportional to the square of the Nd subnetwork magnetization,Ku=CM2Nd.Cwas exponentially dependent on concentration according to the relationC=6 exp(−10x).

ISSN:0021-8979    

DOI:10.1063/1.325172

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The effect of silica on the magnetic properties and microstructure of a manganese zinc ferrite has been studied. It is found that as silica content increases, the magnetic properties at first improve, then deteriorate around 0.04&percent; silica due to discontinuous grain growth. At still higher silica contents, magnetic properties deteriorate further due to an increase in the total effective magnetic anisotropy.

ISSN:0021-8979    

DOI:10.1063/1.325173

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

This paper presents the results of an investigation on the dielectric properties and discusses the observed ac and dc electrical characteristics of aluminum oxide thin films. ac properties are deduced from the capacitance measurements at intermediate and high frequencies. Measurements indicate the existence of two relaxation mechanisms. Hopping polarization of charge carriers is responsible for the high‐frequency dissipation mechanism. This polarization is influenced by an additional mechanism at low frequencies. dc current‐voltage characteristics are obtained from the steady‐state region of the current transients for various step voltages. They exhibit two distinct types of conduction mechanisms depending on the applied voltage: (a) Ohmic conductivity at low voltages and (b) space‐charge‐limited current (SCLC) at high voltages. Specimens are polarized in the upper limit of the Ohmic region. According to the additional effect of the polarization field in a formed sample with respect to applied field, two alternative types of current transients are posible, which are called ’’same’’ and ’’reverse’’ polarity transients. Relaxation frequencies, obtained by means of the current transient data using Hamon’s equation, depend on the applied electrical field. The polarization field also moderates the relaxation frequencies.

ISSN:0021-8979    

DOI:10.1063/1.325174

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The exact form of the Rosencwaig‐Gersho theory for the photoacoustic effect in solids is used to depict how the magnitude and phase of the photoacoustic signal vary with chopping frequency and normalized length. Applications of the theory to studies of film‐substrate systems are discussed.

ISSN:0021-8979    

DOI:10.1063/1.325175

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Impact of 60–200‐keV B+ions on polycrystalline Cu and Mo targets gives rise to emission from backscattered excited Be and B+. The emission coefficients for these lines are presented as a function of impact energy and analyzed to provide a measure of the survival parameterA/afor the atom or ion recoiling from the target. For B recoiling from both Cu and Mo, this is found to be 1.3×108cm/sec, while for recoiling B+, it is 2.4×108. In the case of recoiling B+, the radiationless deexcitation must be by the Auger mechanism. Emission coefficients for the 3247, 3274‐A˚ Cu I doublet are also presented and rise slowly throughout the energy range studied.

ISSN:0021-8979    

DOI:10.1063/1.325176

出版商:AIP    

年代:1978

数据来源: AIP