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Journal ArticleDOI

Growth of high purity semiconductor epitaxial layers by liquid phase epitaxy and their characterization

S. Dhar1
01 Jul 2005-Bulletin of Materials Science (Springer Science and Business Media LLC)-Vol. 28, Iss: 4, pp 349-353
TL;DR: In this article, the authors describe the growth of several III-V epitaxial semiconductor materials in high purity form by liquid phase epitaxy (LPE) technique and the step-by-step procedures adopted to reduce impurities.
Abstract: This paper briefly describes our work and the results on the growth of several III-V epitaxial semiconductor materials in high purity form by liquid phase epitaxy (LPE) technique. Various possible sources of impurities in such growth are listed and step-by-step procedures adopted to reduce them are discussed in particular reference to the growth of GaAs layers. The technique of growing very high purity layers by treating the melt with erbium is described for the growth of InGaAs and GaSb layers.

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Citations
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Book ChapterDOI
01 Jan 2017
TL;DR: In this article, three basic techniques, liquid phase epitaxy (LPE), metal organic chemical vapor deposition (MOCVD), and molecular beam epitaxial (MBE), are discussed.
Abstract: Epitaxial growth of thin films of material for a wide range of applications in electronics, optoelectronics, and magneto-optics is a critical activity in many industries. The original technique, in most instances, was liquid-phase epitaxy (LPE) as this was the simplest and often the cheapest route to producing device-quality layers. While some production processes are still based on LPE, most of the research activities and, increasingly, much of the production of electronic and optoelectronic devices is now centered on metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE). These latter techniques are more versatile, although the equipment is more expensive, and can readily produce multilayer structures with atomic-layer control, which is becoming more and more fundamental to the nanoscale engineering being called upon now to produce device structures in as-grown multilayers. This chapter covers these three basic techniques, including some of their more common variants, and outlines the relative advantages and disadvantages of each of them. Some examples of growth in various materials systems of importance are also outlined for each of the three techniques.

29 citations

Book ChapterDOI
01 Apr 2010
TL;DR: In this paper, the authors proposed the use of rare-earth (RE) elements in semiconductor technology and applied it in the field of optical amplifiers and laser based on REdoped fibres for optoelectronics.
Abstract: First applications of rare-earth (RE) elements in semiconductor technology are rooted in radiation tolerance improvements of silicon solar cells and purification of GaP crystals. The idea was later adopted in the technology of germanium and compound semiconductors. Since the 1980’s, considerable attention has been directed towards REs applications in III-V compounds both for epitaxial films and bulk crystals (Zakharenkov et al., 1997). The uniqueness of REs arises from the fact that the lowest-energy electrons are not spatially the outermost electrons of the ion, and thus have a limited direct interaction with the ion’s environment. The shielding of the 4f electrons by the outer filled shells of 5p and 5s electrons prevents the 4f electrons from directly participating in bonding (Thiel et al., 2002). The RE ions maintain much of the character exhibited by a free ion. This non-bonding property of the 4f electrons is responsible for the well-known chemical similarity of different REs. Since transitions between the electronic states of the shielded 4f electrons give rise to spectrally narrow electronic transitions, materials containing REs exhibit unique optical properties. By careful selection of the appropriate ion, intense, narrow-band emission can be gained across much of the visible region and into the near-infrared (Kenyon, 2002). Inspired by the striking results accomplished in the field of optical amplifiers and lasers based on REdoped fibres (Simpson, 2001), substantial research activity has been recently carried out on RE-doped semiconductor materials for optoelectronics (Klik et al., 2001). In most cases, however, achieving effective doping of III-V compounds by REs during growth from the liquid phase has proven difficult; the high chemical reactivity and the low solid solubility are the main restrictions on introducing RE atoms into the crystal lattices (Kozanecki & Groetzschel, 1990). On the other hand, the enhanced chemical affinity of REs towards most species of the shallow impurities leads to the formation of insoluble aggregates in the melt. Under suitable growth conditions, these aggregates are rejected by the growth front and are not incorporated into the grown layer: gettering of impurities takes place. Especially Si and main group-six elements acting as shallow donors in III-V semiconductors are effectively gettered due to REs high affinity towards them (Wu et al., 1992). Removal of detrimental impurities is of vital importance in applications such as PIN 13

6 citations


Cites background from "Growth of high purity semiconductor..."

  • ...There are several sources of impurities that may be introduced into the grown layer (Dhar, 2005):...

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  • ...There are several sources of impurities that may be introduced into the grown layer (Dhar, 2005): - Source materials and chemicals to clean them....

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Journal ArticleDOI
TL;DR: In this article, the liquid phase epitaxial growth of Zn 3 P 2 on InP (1.0) substrates by conventional horizontal sliding boat system using 100% In solvent was reported.
Abstract: We report the liquid-phase epitaxial growth of Zn 3 P 2 on InP (1 0 0) substrates by conventional horizontal sliding boat system using 100% In solvent. Different cooling rates of 0.2–1.0 °C/min have been adopted and the influence of supercooling on the properties of the grown epilayers is analyzed. The crystal structure and quality of the grown epilayers have been studied by X-ray diffraction and high-resolution X-ray rocking measurements, which revealed a good lattice matching between the epilayers and the substrate. The supercooling-induced morphologies and composition of the epilayers were studied by scanning electron microscopy and energy dispersive X-ray analysis. The growth rate has been calculated and found that there exists a linear dependence between the growth rate and the cooling rate. Hall measurements showed that the grown layers are unintentionally doped p-type with a carrier mobility as high as 450 cm 2 /V s and a carrier concentration of 2.81×10 18 cm −3 for the layers grown from 6 °C supercooled melt from the cooling rate of 0.4 °C/min.

6 citations

Journal ArticleDOI
TL;DR: In this paper, the Schottky barrier is constructed on InP epitaxial layers prepared by liquid-phase epitaxy from rare-earth treated melts using metal nanoparticles and a graphite layer.
Abstract: Fabrication of high-quality Schottky barriers on InP epitaxial layers prepared by liquid-phase epitaxy from rare-earth treated melts is reported The Schottky structures are based on metal nanoparticles and a graphite layer deposited from colloidal solutions onto epitaxial layers with varying carrier concentration The structures have notably high values of the barrier height and of the rectification ratio giving evidence of a small degree of the Fermi-level pinning Electrical characteristics of these diodes are shown to be extremely sensitive to the exposure of gas mixtures with small hydrogen content

5 citations

Journal ArticleDOI
TL;DR: In this article, Zn3As2 epitaxial layers were grown on GaAs (1 0 0) substrates by liquid phase epitaxy (LPE) using Ga as the solvent.
Abstract: Zn3As2 epitaxial layers were grown on GaAs (1 0 0) substrates by liquid phase epitaxy (LPE) using Ga as the solvent. Zinc mole fraction in the growth melt was varied from 1.07 x 10(-2) to 6 x 10(-2). X-ray diffraction spectrum exhibits a sharp peak at 43.3 degrees characteristic of Zn3As2 crystalline layer. The peak intensity increases with increase in zinc mole fraction in the growth melt. The compositions of the as-grown Zn3As2 layers were confirmed by energy dispersive X-ray (EDX) analysis. Surface morphology was studied using scanning electron microscopy (SEM) and the thickness of the epilayers was also determined. The Hall measurements at 300 K indicate that Zn3As2 epilayers are unintentionally p-doped. With an increase of zinc mole fraction in the growth melt, carrier concentration increases and carrier mobility decreases. Infrared optical absorption spectroscopy showed a sharp absorption edge at 1.0 eV corresponding to the reported band gap of Zn3As2. (C) 2010 Elsevier B.V. All rights reserved.

4 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the incorporation of the lanthanide element erbium in GaAs during growth by liquid phase epitaxy is investigated by low-temperature photoluminescence measurements.
Abstract: The incorporation of the lanthanide element erbium in GaAs during growth by liquid‐phase epitaxy is investigated by low‐temperature photoluminescence measurements. After an anneal of the epitaxial layers at 850 °C, a characteristic Er‐associated optical transition appears at a wavelength of ∼1.55 μm, however, no erbium‐related photoluminescence signal is found in the as‐grown GaAs:Er layers. The Zeeman splitting of the new photoluminescence lines reveals a cubic symmetry of the optically active Er complex. Successive mechanical polishing and annealing of the layers provides evidence for the incorporation of Er within the layer as an optically inactive Er complex, which is activated only at the surface by thermal annealing.

63 citations

Journal ArticleDOI
TL;DR: In this paper, epilayers were grown on semi-insulating (100) Fe-doped InP substrates using liquid phase epitaxy (LPE) using rare-earth doped melts in a graphite boat.
Abstract: High‐quality In0.53Ga0.47As epilayers have been grown on semi‐insulating (100) Fe‐doped InP substrates. The growths were performed by liquid phase epitaxy (LPE) using rare‐earth‐doped melts in a graphite boat. The rare‐earth elements studied were Yb, Gd and Er which act as gettering agents of impurities. Hall measurements show an elevated electron mobility for rare‐earth‐treated samples over undoped samples, μe=11 470 cm2/V s at 300 K and reduced carrier concentration (n‐type), 9.33×1013 cm−3. The Hall results indicate an improvement in layer quality, but suggests that the treated layers are compensated. Photoluminescence (PL) studies show that the layers grown from rare‐earth‐doped melts have higher integrated PL efficiency with narrower PL linewidths than the undoped melt growths. The grown materials were fully characterized by Fourier transform infrared spectroscopy, double‐crystal x‐ray diffraction, energy dispersive spectroscopy, secondary‐ion‐mass spectroscopy, and deep level transient spectroscopy ...

29 citations

Journal ArticleDOI
TL;DR: In this article, hole traps with optical ionization energies of 0.65 and 0.79 eV are revealed in the material which are assumed to be two levels associated with the hole trap B reported in the literature.
Abstract: Photocapacitance measurements in the photon energy range of 0.64 to 1.27 eV are done on GaAs layers grown by liquid phase epitaxy (LPE) and doped with varying amounts of indium (In) and antimony (Sb). Two hole traps with optical ionization energies of 0.65 and 0.79 eV are revealed in the material which are assumed to be two levels associated with the hole trap B reported in the literature. In addition, the hole trap A, usually found in LPE GaAs is also detected here by optical deep level transient spectroscopy (ODLTS) technique. The results of trap density measurements, as functions of isoelectronic doping concentration, indicate that VGa is an active constituent of the hole traps in LPE GaAs. The concentration of the 0.79 eV trap is found to be reduced in the material with high concentration of Sb. The analysis of photocapitance data using the existing theoretical models indicates the presence of an electron trap with activation energy of 0.75 eV in the heavily Sb-doped material. This trap may be identified with the second charge state of the SbGa electron trap, obtained previously in bulk and metalorganic vapor phase epitaxial GaAs doped with Sb. The sharp reduction of the 0.79 eV hole trap density in Sb-doped materials is explained by assuming the complex GaAsV, as its source.

9 citations

Journal ArticleDOI
TL;DR: In this article, a detailed analysis of the temperature-dependent Hall mobility data for the samples using a theoretical curve fitting technique revealed that the donor impurities in the material are reduced to a greater extent compared to the acceptors, making the layers compensated.
Abstract: Hall mobility and carrier concentration measurements are done on In0.53Ga0.47As layers grown by liquid phase epitaxy from melts containing 0.1–0.18 wt % Er. The carrier concentration in the layer decreased to 2×1014 cm−3 upon the addition of 0.16 wt % Er to the growth melt but the corresponding mobility of the layer increased only marginally. A detailed analysis of the temperature-dependent Hall mobility data for the samples using a theoretical curve fitting technique revealed that the donor impurities in the material are reduced to a greater extent compared to the acceptors, making the layers compensated. The experimental mobilities are further compared with the published values of theoretically calculated mobilities for InGaAs with similar compensations. It is shown that the space charge scattering effects are to be considered in order to get a good agreement between the experimental and the theoretical values.

7 citations

Journal ArticleDOI
TL;DR: In this article, the presence of an electron trap with activation energy of 0.17 eV in the Er-doped In0.53Ga0.47 was confirmed from deep level transient spectroscopy experiments on undoped layers.
Abstract: Detailed properties of In0.53Ga0.47As layers grown by liquid phase epitaxy from melts containing 0.04 and 0.1 wt % Er are reported. The carrier concentration in the material is reduced by almost two orders of magnitude as a result of Er doping. Low temperature photoluminescence measurements indicate that both the donor and the acceptor type impurities are gettered by Er and the full-width at half-maximum of the major peak is reduced to 4 meV for the layer with the highest Er doping. From deep level transient spectroscopy experiments on undoped layers, we confirm the presence of an electron trap with activation energy of 0.17 eV. Density of this trap is reduced by more than two orders of magnitude in the Er doped material and another electron trap with activation energy of 0.15 eV is revealed from the analysis of the experimental data. We associate the 0.17 eV trap with impurities in the material. From low temperature photoconductivity and photocapacitance experiments, we further confirm that Er creates a ...

6 citations