Antimony In Germanium Research Articles

High-level incorporation of antimony in germanium by laser annealing

In this work we investigate pulse laser annealing as an alternative approach to reach high-level incorporation of Sb in substitutional location in crystalline germanium. Laser irradiation is demonstrated to recover also those structural defects, like honeycomb structures, that form during high-fluence heavy-ion implantations in Ge and that cannot be eliminated by conventional thermal treatments. Indeed, concentrations of substitutional Sb higher than 1×1021 at./cm3 have been obtained, well above the solid solubility of Sb in Ge. The strain induced on the Ge host lattice is also investigated, evidencing that the obtained Sb doped Ge layer is pseudomorphic to the Ge substrate while positively strained by the substitutional Sb atoms present within the Ge matrix. The kinetics of this Sb-rich Ge alloy phase is finally investigated, showing that most of Sb goes out of lattice with increasing the annealing temperature up to 488 °C, leading to a decrease in the related lattice deformation. These results are very relevant for the future high-mobility channel technology.

Diffusion and defect reactions between donors, C, and vacancies in Ge. I. Experimental results

The diffusion of self-atoms and $n$-type dopants such as phosphorus, arsenic, and antimony in germanium was studied by means of isotopically controlled multilayer structures doped with carbon. The diffusion profiles reveal an aggregation of the dopants within the carbon-doped layers and a retarded penetration depth compared to dopant diffusion in high-purity natural Ge. Dopant aggregation and diffusion retardation are strongest for Sb and similar for P and As. In addition, the shape of the dopant profiles changes for dopant concentrations in the range of ${10}^{20}\text{ }{\text{cm}}^{\ensuremath{-}3}$ mainly due to the formation of dopant-vacancy complexes, which is more significant at high concentrations. Accurate modeling of the simultaneous self-diffusion and dopant diffusion is achieved on the basis of the vacancy mechanism and additional reactions that take into account the formation of neutral carbon-vacancy-dopant and neutral dopant-vacancy complexes. The stability of these complexes is compared to theoretical calculations published recently and to additional calculations presented in Part II. The overall consistency between the experimental and theoretical results supports the stabilization of donor-vacancy complexes in Ge by the presence of carbon and the dopant deactivation via the formation of dopant-vacancy and carbon-vacancy-dopant complexes.

Estimation of liquid phase diffusion coefficients of gallium and antimony in germanium from segregation data in crystal growth experiments

The objective of this paper is to propose new determinations of the diffusion coefficients of gallium and antimony in liquid germanium. To do so, an analysis of effective segregation coefficients obtained in Czochralski growth experiments is carried out in the frame of a self-consistent solidification model. As such, the deduced diffusivity values should be taken as more reliable than previously published data based on the analysis of solute segregation profiles, but the accuracy of the technique is limited by the scatter of the composition measurements. Comparison with existing data supports the necessity of setting up a dedicated experimental program for the measurement of liquid phase diffusion coefficients in germanium.

Intrinsic and extrinsic diffusion of phosphorus, arsenic, and antimony in germanium

Diffusion experiments of phosphorus (P), arsenic (As), and antimony (Sb) in high purity germanium (Ge) were performed at temperatures between 600 and 920 °C. Secondary ion mass spectrometry and spreading resistance profiling were applied to determine the concentration profiles of the chemically and electrically active dopants. Intrinsic and extrinsic doping conditions result in a complementary error function and box-shaped diffusion profiles, respectively. These profiles demonstrate enhanced dopant diffusion under extrinsic doping. Accurate modeling of dopant diffusion is achieved on the basis of the vacancy mechanism taking into account singly negatively charged dopant-vacancy pairs and doubly negatively charged vacancies. The activation enthalpy and pre-exponential factor for dopant diffusion under intrinsic condition were determined to 2.85 eV and 9.1 cm2 s−1 for P, 2.71 eV and 32 cm2 s−1 for As, and 2.55 eV and 16.7 cm2 s−1 for Sb. With increasing atomic size of the dopants the activation enthalpy decreases. This is attributed to differences in the binding energy of the dopant-vacancy pairs.

Donor-acceptor interaction and mutual solubility of the Cu and Sb components in the Ge-Cu-Sb ternary system

The limiting solubilities of copper and antimony in germanium at 773 and 873 K were determined by measuring microchardness of solid solution crystals. The solubility of copper was found to increase substantially in the presence of antimony. This observation was explained based on concept of donor - acceptor interactions resulting in the formation of the (CuSb) charges complex. An analytic expression for the solubility of donors (antimony) as a function of the content of acceptors (copper) and vice versa was obtained. These relations were used to calculate the cosolubility of doping elements in the Ge–Cu–Sb system. The calculated and experimental solubility values were in close agreement with each other.

Dopant incorporation in epitaxial germanium grown on Ge(100) substrates by MBE

We have conducted the first studies of dopant incorporation (gallium, boron, and antimony) in MBE germanium grown on Ge(100) substrates. Excellent germanium films have been grown on Ge substrates with little demarcation of the substrate-epi interface. A first order kinetic incorporation model has been used to describe the behavior of gallium in germanium. Gallium doping of germanium takes place through an adlayer at the growth front and between growth temperatures of 450 and 550°C successful p-doping of germanium by gallium can be accomplished. Boron is an excellent p-dopant in germanium with good activation at high concentrations and sharp transition profiles. The incorporation of antimony in germanium at growth temperatures ≥ 450°C is poor and needs further investigation.

Pulse-laser-induced supersaturation of indium and antimony in germanium: E M Lawson,J Appl Phys, 53 (9), 1982, 6459–6460

Pulse-laser-induced supersaturation of indium and antimony in germanium: E M Lawson,J Appl Phys, 53 (9), 1982, 6459–6460

Pulse-laser-induced supersaturation of indium and antimony in germanium

A pulsed ruby laser has been used to produce enhanced solubilities of indium and antimony in germanium. Lower limits for the solubilities have been obtained using Rutherford backscattering spectrometry and electrical measurements. The values obtained are ≳5.3×1020 cm−3 for indium and ≳6.2×1020 cm−3 for antimony.

On the Production of Diffused Layers in Germanium

Experimental studies are conducted for the diffusion of antimony in germanium in the following systems: (1) Sealed tube method, i.e. diffusion in a sealed vessel under vacuum.(2) Diffusion in a half-open system, by which the diffusant is carried over the wafer under vacuum.(3) Carrier gas diffusion (open system).(4) Diffusion with the powder method, by which the diffusion takes place in the solid phase using a powdered diffusant brought in direct contact with the wafer.The final results are compared. It is found that the sealed tube system offers most advantages for the diffusion in germanium.

Effect of the concentration gradient of indium on the diffusion of antimony in germanium

Effect of the concentration gradient of indium on the diffusion of antimony in germanium

Zeeman Spectra of Arsenic and Antimony in Germanium in an Intermediate Magnetic Field

The Zeeman spectra of arsenic and antimony donors in germanium were measured at liquid helium temperature with a static magnetic field along a [111] direction and up to 46 kOe. The Zeeman spectral lines of 2 p 0 , 2 p ±1 and 3 p ±1 were compared with the theory presented in a preceding paper. As a result, it was substantiated that the description of these donor levels can be well approximated by accounting only the longitudinal-axis component of the magnetic field for each velley, and also that the higher the levels the transformation from the weak approximation to the strong field approximation occurs at lower fields, The splitting of the ground states in the presence of a magnetic field was found to coincide with the theoretical prediction including the central-cell correction treated phenomenologically besides the magnetic field effect. On the basis of these comparison all the remaining absorption peaks were assigned to the hydrogen-like levels or the bound Landau levels.

Effect of ultrasonic treatment on the diffusion of antimony in germanium: Abranov, O.V., Gorelik, S.S., Grabchak, V'.P., Soviet Physics—Solid State, Vol 10, No 8 (February 1969) pp 1972–1973 (1392)

Effect of ultrasonic treatment on the diffusion of antimony in germanium: Abranov, O.V., Gorelik, S.S., Grabchak, V'.P., Soviet Physics—Solid State, Vol 10, No 8 (February 1969) pp 1972–1973 (1392)

Solid state diffusion of antimony in germanium, from the vapour phase, in a vacuum furnace: G N Wills, Solid State Electronics, 10, 1967, 1–8

Solid state diffusion of antimony in germanium, from the vapour phase, in a vacuum furnace: G N Wills, Solid State Electronics, 10, 1967, 1–8

Solid state diffusion of antimony in germanium, from the vapour phase, in a vacuum furnace

Solid state diffusion of antimony in germanium, from the vapour phase, in a vacuum furnace

Solid state diffusion of antimony in germanium, from the vapour phase, in a vacuum furnace

The diffusion of antimony into germanium in a two zone vacuum furnace has been investigated by a 4-point probe technique. Graphs are given of the variation of the antimony concentration on the surface of the germanium with temperature and time, also that of the depth of the diffused p- n junction. Simple analyses of the antimony concentration profiles with surface concentrations below 1 × 10 18 atoms cm −3 gave a diffusion constant D 0 of 507 cm 2 sec −1 with an activation energy of 2·8 eV. Further analyses on accurately determined profiles, show anomalous behaviour of the diffusion below 5 × 10 17 atoms cm −3.

Diffusion of antimony in germanium during plastic straining

Diffusion of antimony in germanium during plastic straining

The effect of dislocations on diffusion in germanium

Diffusivities of antimony and indium have been measured in specially deformed germanium specimens. The diffusivity of antimony has been measured 1. (1) parallel to a high density array of parallel edge dislocations, 2. (2) perpendicular to this array, and 3. (3) in low dislocation, non-deformed material. The diffusivity of indium was measured in heavily deformed and in non-deformed germanium specimens. The results of these experiments indicate that the array of parallel dislocations in densities of between 10 6 and 10 7 cm −2 has no effect upon the diffusion of antimony in p-type germanium. Neither an anisotropy of diffusion rates with respect to the dislocation direction nor a difference in diffusivities in deformed and undeformed material was detected. Similarly, the introduction of high densities of dislocations has no measureable effect upon the diffusion of indium into n-type germanium.

Antimony concentration in Germanium in equilibrium with the vapor from a bismuth-antimony alloy

The equilibrium concentration of antimony in germanium is computed as a function of the germanium temperature and of the composition and temperature of a liquid antimony-bismuth alloy, which determines the antimony vapor pressure in a closed system containing the germanium.

Solid Solubilities of Antimony, Arsenic, and Bismuth in Germanium from a Saturation Diffusion Experiment

not Available.

Field-retarded diffusion of antimony in germanium

Diffusion techniques, applied to semiconductors to produce impurity gradients, have revealed that under certain conditions Fick's law is not always obeyed. It will be shown experimentally and theoretically that a field-retarded diffusion of antimony will occur in germanium in the presence of a p-type impurity, e.g. gallium, which is higher in concentration and has a negative gradient in the direction of the donor diffusion. This implies, in addition, temperature settings whereby the intrinsic carrier concentration n i is smaller than N A, the number of ionized p-type impurity atoms. The investigations have been carried out for a temperature range of 700–900°C and with concentration levels of N A ≤ 10 20atoms/cm 3 and of N D ≤ 10 19atoms/cm 3. By including field terms it is shown that the diffusion constant of antimony D Sb is dependent upon the ratio of its concentration N D to the intrinsic carrier concentration n i, and the ratio of acceptor and donor gradients. The experimental evidence is in general agreement with the theoretical formulation.