Copper In Germanium Research Articles

A “rod-flame” system in direct laser enhanced ionization analysis of high-purity substances

Laser enhanced ionization in conjunction with electrothermal microsample evaporation from a heated graphite rod into the flame has been used for the direct analysis of high-purity germanium and CdHgTe alloys. Methods for determining microquantities of copper in germanium and indium in these alloys have been developed. Samples in the form of both solutions and powders of 1–20 mg in weight are used. The interferences of the sample matrix in the two cases are shown to be small and consist of additive ionization background. The detection limit for indium in the CdHgTe solutions is as low as 10 −4 μg g and with the solid samples it can be reduced to 10 −6 μg g . For determinations of copper in germanium, the detection limit is higher since it is limited by the rod material purity. The germanium and CdHgTe samples are analysed using the standard addition and calibration curve methods. A good correlation of the results obtained for the solutions and powders through calibration with aqueous standard solutions indicates that the approach proposed in this work ensures direct analysis of the solid and liquid samples with a high accuracy.

DLTS of the third acceptor level of substitutional copper in germanium

DLTS results of the third acceptor level of substitutional copper in n-type germanium are presented for the first time. Accurate determination of the signature and the temperature dependence of the electron capture cross section yields an energy level of EC-0.26 eV in agreement with the Hall effect. It is shown that two DLTS bands attributed in the literature to the third copper level should correspond to other defects.

Convenient method for the determination of trace amounts of germanium by hydride generation direct current plasma atomic emission spectrometry: interference reduction by L-cystine and L-cysteine

A convenient and rapid method for the determination of trace amounts of germanium has been developed. This method has the advantage that it is less sensitive to instrumental parameters than previously described methods. Interferences from transition elements are reduced and interferences from other hydride-forming elements are negligible. The detection limit for the determination of germanium is 20 pg ml–1(3σ). Germanium concentrations in metallurgical samples are easily determined and this method has been applied to the determination of germanium in copper and iron.

Identification of Interstitial Copper and Its Pair with Substitutional Copper in Germanium

Identification of Interstitial Copper and Its Pair with Substitutional Copper in Germanium

Isotope-induced symmetry change in dynamic semiconductor defects.

Two hydrogen nuclei and a hole bind to the triple-acceptor copper in germanium. The result is a single acceptor whose electronic states are modified by coupling to the zero-point motion of the nuclei. That motion displays a qualitative change from rotation to libration induced by an increase in hydrogen isotopic mass. The acceptor $A(\mathrm{Cu}{\mathrm{H}}_{2})$ has full tetrahedral symmetry and a complex ground-state manifold. All heavier isotope combinations display only a single ground-state component of symmetry lower than tetrahedral.

Diffusion and solubility of copper in germanium

Diffusion profiles and the solubility of Cu in Ge were measured in the temperature interval 850–1200 K by means of the spreading-resistance technique. From these data it is concluded that the diffusion of Cu in Ge involves the interchange between a highly mobile interstitial configuration, Cui, and a practically immobile substitutional configuration, Cus, with the aid of vacancies, V, via the so-called dissociative mechanism, Cui+V⇄Cus. The excellent agreement of the values of the vacancy contribution to the tracer self-diffusion coefficient in Ge, as calculated from our diffusivity and solubility data on Cu in Ge, with directly measured values of the 71Ge tracer self-diffusion coefficient from the literature demonstrates that self-diffusion in Ge occurs via vacancies. A comparison with the mechanisms of Au and self-diffusion in Si is presented.

In-Diffusion and Annealing of Copper in Germanium

The in-diffusion and anealing of copper in germanium are examined experimentally over the temperature range 600 to 805°C, and using the experimental results, discussions are made as to whether the dissociative mechanism or the kick-out mechanism is at work in these processes. The experimental results support the theory that copper in germanium diffuses by the dissociative mechanism and the dominant point defects in germanium are vacancies.

Cantilever-type displacement sensor using diffused silicon strain gauges

Two kinds of alloys have been developed as cantilever and solder materials which are suitable for semiconductors. The cantilever material is an ironnickelcobalt ternary alloy that has a high elasticity with a tensile strenght of 1GPa, and a low thermal expansion coefficient 50 × 10 −7/K. The material for the solder is goldcoppergermanium ternary eutectic alloy that has a tensile strength of 1.1 GPa. Two strain gauges were diffused in parallel on a silicon pellet, and the pellet was bonded by the alloy solder on each surface of the cantilever, taking into account linearity and temperature effect. It was confirmed that the linearity was less than ±0.1% and a zero-point shift was under ±0.1% after 10 7 repeated stresses. The temperature effect was less than ±05% over a range of 230 – 390K using a non-linear compensation.

Grandeurs thermodynamiques de formation des solutions solides binaires diluées CuM lorsque m décrit la première longue période

The enthalpies of mixing of binary dilute solutions of the solutes manganese, iron, cobalt, nickel, gallium and germanium in copper were measured by liquid tin calorimetry. The excess free enthalpies of binary dilute solutions of the solutes titanium, chromium, manganese, iron, cobalt, nickel, gallium and germanium in copper were determined by solid cell e.m.f. measurements. The experimental results for chromium, manganese, iron and cobalt in copper are compared with data calculated using phase diagrams. This method is also used to calculate data for CuV. In the final discussion enthalpies of mixing and excess free enthalpies are compared. The experimental results are discussed in relation to the theoretical calculations of Parlebas.

Density functional approach to point defect properties of copper–germanium alloys

AbstractPoint defect properties of copper–germanium alloys are studied by using a recently developed method which is based on the density functional formalism. The charge density is approximated by superimposing the charge densities of the respective free atoms. The kinetic energy is obtained from a modified Thomas‐Fermi‐v. Weizsäcker expression. To test the reliability of this method, some properties of the perfect copper lattice and of Cu2 and Ge2 molecules are studied. Results on the formation energy of vacancies and divacancies in copper are presented. Further calculations are concerned with the interaction energy of two Ge atoms embedded in Cu and with the influence of two neighbouring Ge impurities on the formation energy of a vacancy in copper.

Isotope effect for diffusion of germanium in copper and copper-germanium solid solutions

The isotope effect for diffusion of 68Ge and 77Ge has been measured in pure copper and copper-germanium alloys employing their positron and electron emission. The high-energy particles chosen were separated in a magnetic spectrometer. The half-life of 77Ge could be determined as (672.6 ± 1.7) min, in excellent agreement with literature data. The most probable values for the correlation factor ƒ Ge are 0.52 ± 0.03 for infinite dilution, 0.55 ± 0.03 for 5.12 at. % Ge and 0.70 ± 0.02 at 9.52 at. % Ge. The data are discussed in the framework of the statistical alloy model of Manning, which is supposed to be less applicable due to the effective binding of Ge atoms to vacancies. Nevertheless, this model turns out to be not a bad approximation—apparently caused by complex formation of vacancies with more than one impurity atom enhanced by the binding and the associated decorrelation.

Resistance alloy for low temperatures

A ductile copper–germanium alloy shows a negative relative temperature coefficient of resistivity of a few parts in 106/K in the temperature range of 1.5–4.2 K. Resistors based on this material are studied for stability under thermal cycling.

The solubility and diffusion of copper in germanium

Abstract From a review of the data on the solubility of copper in germanium, it is concluded that the substitutional and interstitial equilibrium solubilities maybe described by respectively, over the temperature range 450-950°c. From these values it is shown that the activation energy of D 1 (the effective coefficient of inter-stitially limited dissociative diffusion) will be slightly less than the activation energy of true interstitial diffusion. This is shown to be consistent with the difficulty, found earlier, of determining a temperature dependence for the measured high diffusion coefficients for Cu in Ge. It is also shown that the obtained from the above Gs' and the self-diffusion coefficient for germanium, is consistent with the lower diffusion coefficients measured for Cu in Ge. This supports the interpretation of the tracer self-diffusion coefficient of germanium in terms of a monovacancy mechanism.

Thermally Activated Dislocation Depinning in Dilute Copper Alloys

Internal friction and Young's modulus measurements have been performed on a series of dilute copper—silicon, copper—germanium, and copper—tin alloys at temperatures ranging from 4° to 300°K in order to determine the extent of thermally activated dislocation depinning from solute atoms. Specimens are in the form of singel-crystal bars, and are excited piezoelectrically in their fundamental longitudinal mode of vibration at 80 kHz. For temperatures in excess of 180°K, the amplitude-dependent internal friction is characterized by an Arrhenius temperature dependence with an activation energy that varies linearly with the stress amplitude. A low-temperature modification of the Granato—Lücke theory accounts for the temperature dependence of the internal friction below about 120°K; however, the stress dependence is contradictory to that predicted theoretically. In general, thermal depinning is enhanced at high temperatures and stress levels, and in crystals containing long dislocation segment lengths and solute atoms of low pinning strength.

Solute atom-dislocation binding in dilute copper alloys

Internal friction experiments have been performed on [100] oriented single crystals of dilute coppersilicon and copper-tin alloys in an attempt to determine the binding potential energies of silicon and tin solute atoms to dislocations and to compare the results with the value recently obtained for germanium in copper. Comparison of the measured values allows a test of binding energy theory since the three solute species are of different size, yet exhibit similar electrical and chemical interactions in solution. The measurements have been made using the Marx composite oscillator technique with the specimen driven in its fundamental mode of longitudinal vibration at a frequency of 80 kc/s at temperatures between 198° and 579°C. The strain amplitude dependence of the hysteretic decrement is in good agreement with predictions of the Granato-Lücke theory of dislocation damping and analysis of the data yields values for the solute atom-dislocation binding potential energy of −0.16 ± 0.02, −0.22 ± 0.06 and −0.40 ± 0.10 eV for silicon, germanium and tin, respectively. These values are in general agreement with the predictions of theory and indicate that the dominant contribution to the binding potential energy is due to the size misfit of the solute atoms. In addition, values for the solute atom-dislocation binding entropy are found to be 3.0 ± 0.4 k, 2.0 ± 0.9 k and −0.2 ± 1.5 k (k is Boltzmann's constant) for silicon, germanium and tin, respectively.

Some observations on the mechanical properties of a ζ H.C.P. Copper–Germanium phase

Abstract This work was undertaken at the kind suggestion of Dr. T. B. Massalski, to whom I am very grateful for help and encouragement. I have also greatly benefited from the comments of Professors R. W. Cahn and P. Haasen and Drs. R. L. Bell, H. W. King and H. S. Rosenbaum on this manuscript. Dr. L. F. Vassamillet made the microprobe analyses and Mr. J. Escajeda assisted in part of the experimental work. This work has been supported in part by the Atomic Energy Commission. A method for growing single crystals of a copper–13·5 at. % germanium alloy and having approximately the ideal axial ratio is described. The only tensile deformation modes found were basal slip, and {10·11} twinning and cleavage. Basal slip occurred with pronounced yield drops at temperatures below 450°C and marked jerky flow was found in the temperature range 170–450°C. No lüders band was observed; basal slip below 450°C occurred in very narrow zones with very high shear strains. The yield phenomena are inferred to be due to a dislocation unlocking process rather than a multiplication process.

Heat of formation of the solid solutions of zinc, gallium and germanium in copper

The heats of formation of the solid solutions of zinc, gallium and germanium, in copper have been determined by liquid tin solution calorimetry. The results for copper-zinc and copper-gallium are consistent with the predictions of the Friedel theory of metallic solutions.

Infra-red Investigation of the Acceptor Levels Formed by Copper in Germanium

Infra-red absorption measurements from 1 to 34 μ have been made on germanium containing varying amounts of antimony and copper at temperatures down to 20°K. The results indicate that the three acceptor levels introduced by copper into germanium can be identified by their effect on the low temperature absorption spectra of suitably doped samples. The appearance of the levels is in good agreement with the existing theory, and in addition to this, an excited state of the shallow acceptor level has been identified which has not been previously reported.

Calculation of the Heat of Solution of Copper in Germanium from Diffusion Measurements

The diffusion of substitutional copper in germanium below 700°C has been explained by a dissociation mechanism proposed by Frank and Turnbull. It is shown that this mechanism provides a means for estimating the heat of solution of copper in germanium by measuring the activation energies for substitutional copper diffusion and for self-diffusion in germanium.

A Note on the Theory of Diffusion of Copper in Germanium

The theory of Frank and Turnbull of the diffusion of copper in germanium is extended to take into account the finite rate of generation of vacancies in the bulk, and the finite reaction rate in the postulated dissociation of a substitutional copper atom into an interstitial and a vacancy. Comparison of the extended theory with experiment yields an order of magnitude estimate of 10-8 cm for the effective radius of a dislocation for annihilation of a vacancy. It is shown that this result is consistent with the view that vacancy generation and annihilation occurs at dislocation jogs, provided that the attraction of an edge dislocation for a vacancy is taken into account.