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  • 1
    Electronic Resource
    Electronic Resource
    Interdiffusion of lateral composition modulated (GaP)2/(InP)2 short-period superlattices with different encapsulants (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 1233-1235 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The interdiffusion of lateral composition modulated (GaP)2/(InP) 2 short-period superlattices (SPSs) is reported. The lateral composition modulation is achieved by the strain induced lateral layer ordering (SILO) process. A blueshift in the interband transition is observed by photoluminescence spectroscopy for capless and SiO 2 encapsulated annealed SPSs (800 °C, 5.5 h), while the intensity and wavelength of Si3N4 encapsulated annealed SPSs are only slightly perturbed. From transmission electron microscopy, capless annealed SPSs (800 °C, 5.5 h) retain their lateral composition modulation, however, the (001/2) satellite reflections disappear. For long anneal times (48 h), the interband transition corresponds to that of a In0.50Ga 0.50P alloy, suggesting the lateral composition modulation disappears. The observed lateral interdiffusion coefficient exceeds the vertical by a factor of ∼30, suggesting SPS interdiffusion is enhanced by native point defects. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362860
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  • 2
    Electronic Resource
    Electronic Resource
    Carbon incorporation in InP grown by metalorganic chemical vapor deposition and application to InP/InGaAs heterojunction bipolar transistors (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 4233-4236 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The incorporation of residual carbon has been studied for InP grown at low temperatures using TMIn and PH3 by low-pressure metalorganic chemical vapor deposition. n-type conduction is observed with electron concentrations as high as 1×1018 cm−3, and the electrical activation efficiency is 5%–15%. Carbon incorporation is found to be highly dependent on substrate temperature, suggesting that the rate-limiting step is desorption of CHy (0≤y≤3) from the surface during growth. Hydrogen is also incorporated in the layers during growth. The electron mobilities are lower for C-doped InP than for Si-doped InP. InP/InGaAs heterojunction bipolar transistors with C as the p-type base dopant and either Si or C as the n-type emitter dopant have been fabricated and compared. Devices with a carbon-doped base and emitter showed degraded performance, likely as a result of deep levels incorporated during growth of the emitter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356011
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  • 3
    Electronic Resource
    Electronic Resource
    Column III vacancy- and impurity-induced layer disordering of AlxGa1−xAs-GaAs heterostructures with SiO2 or Si3N4 diffusion sources (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 6813-6818 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experiments are described determining the critical parameters for vacancy- and impurity-induced layer disordering of AlxGa1−xAs-GaAs quantum-well heterostructure (QWH) crystals that utilize SiO2 and Si3N4 diffusion source layers. The SiO2- or Si3N4-capped QWH crystal surface reaches equilibrium with the external annealing ambient by diffusion of Ga and As through the encapsulant layer, thus determining the crystal-surface deviation from stoichiometry and the column III vacancy concentration for layer disordering. By proper design of the QWH crystal, encapsulant layer thickness, and annealing ambient, the SiO2 (Si3N4) can be employed as a column III vacancy source (or mask) or as a Si and O (or N) diffusion source to effect impurity-induced layer disordering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.345070
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  • 4
    Electronic Resource
    Electronic Resource
    Impurity-induced layer disordering in In0.5(Alx Ga1−x)0.5P-InGaP quantum-well heterostructures: Visible-spectrum-buried heterostructure lasers (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 482-487 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Diffusion of Si into quantum-well heterostructures and superlattices employing the high gap III-V quaternary system Iny (AlxGa1−x )1−yP is shown to result in impurity-induced layer disordering. Secondary ion mass spectroscopy, transmission electron microscopy, and photoluminescence data indicate that the diffusion of Si into an InAlP-InGaP superlattice grown lattice matched on GaAs (y≈0.5) results in the intermixing of the layers, thus forming an alloy of average composition. Buried-heterostructure lasers are fabricated using Si layer disordering of In0.5 (Alx Ga1−x )0.5 P p-n quantum-well heterostructures. The disorder-defined stripe-geometry diode lasers operate pulsed at 300 K near 6400 A(ring). Continuous wave operation at λ∼6255 A(ring) is achieved at −47 °C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.343562
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  • 5
    Electronic Resource
    Electronic Resource
    Impurity diffusion and layer interdiffusion in AlxGa1−xAs-GaAs heterostructures (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 1838-1844 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Data are presented and a model describing the diffusion of the donor Si in GaAs from grown-in dopant sources. In addition, the effects of background impurities on Si diffusion and layer interdiffusion in AlxGa1−xAs-GaAs superlattices are described. These results are obtained on epitaxial GaAs samples with alternating doped and undoped layers and on AlxGa1−xAs-GaAs superlattices with doped (Si or Mg) layers. The layer-doped GaAs and the AlxGa1−xAs-GaAs superlattices have been grown using metalorganic chemical vapor deposition and are characterized using secondary ion mass spectroscopy and transmission electron microscopy. Different annealing conditions are used to study the interaction between the grown-in impurities and the native defects of the crystal controlling the diffusion processes. The model describing the impurity diffusion and layer (Al-Ga) interdiffusion is based on the behavior of column III vacancies, VIII, and column III interstitials, IIII, and the control of their concentration by the position of the crystal Fermi level and the crystal stoichiometry. Experimental data show that n-type AlxGa1−xAs-GaAs superlattices undergo enhanced layer interdiffusion because of increased solubility of the VIII defect, while enhanced layer interdiffusion in p-type superlattices is caused by an enhanced solubility of IIII. The model employed is consistent with the experimental data and with the data of previous work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.341759
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  • 6
    Electronic Resource
    Electronic Resource
    Defect-accelerated donor diffusion and layer intermixing of GaAs/AlAs superlattices on laser-patterned substrates (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 5821-5825 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Data are presented showing that donor diffusion and Alx Ga1−x As-GaAs layer intermixing are greatly enhanced in the presence of defects created by crystal overgrowth on locally laser-melted substrates. Accelerated defect and impurity-induced layer disordering, and donor diffusion from a solid source (SiO2 ), a vapor source (Ge), and from a grown-in source (Se) are observed in regions of high defect density. The enhanced donor diffusion and crystal self-diffusion are attributed to an increased density of column-III defects and dislocations in the crystal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.343653
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  • 7
    Electronic Resource
    Electronic Resource
    Si impurity-induced layer disordering of Alx Ga1−x -GaAs quantum-well heterostructures by As-free open-tube rapid thermal annealing (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 6199-6206 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Data are presented describing Si impurity-induced layer disordering (IILD) and Al-Ga interdiffusion in AlxGa1−x As-GaAs quantum-well heterostructures (QWHs) using open-tube rapid thermal annealing (900–1000 °C) in a flowing N2/H2 ambient. The data show that Al-Ga interdiffusion is enhanced by n-type crystal doping and suppressed by p-type doping. By surrounding the active layers of the heterostructure with layers of opposite doping, we show that the surrounding layers modify the interdiffusion by controlling the diffusion of point defects to the active layers of the heterostructure. Data are presented showing the effects of dielectric encapsulation (SiO2, Si3N4 ) on Al-Ga interdiffusion. The data show that regardless of doping SiO2 enhances interdiffusion as compared to Si3N4. To achieve more thorough layer intermixing of AlxGa1−x As-GaAs QWHs, Si IILD is also investigated in the high-temperature As-poor regime. The experimental data show that in a high-temperature As-poor annealing ambient, little or no Si diffusion occurs from an elemental Si source in contact with a p-type GaAs QWH cap layer. To achieve Si diffusion under these conditions requires removal of the GaAs cap and the use of Al-reduced SiO2 or Si3N4 as a Si diffusion source. Based on secondary-ion mass spectroscopic measurements, direct comparison of Si diffusion from closed-tube (825 °C, 48 h) and open tube (1000 °C, 10 min) anneals shows increased Si incorporation and layer disordering at higher temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346911
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  • 8
    Electronic Resource
    Electronic Resource
    Improved thermal stability of AlGaAs–GaAs quantum well heterostructures using a "blocking'' Zn diffusion to reduce column-III vacancies (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1859-1861 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Data are presented on the reduction of layer intermixing (disordering) in AlGaAs–GaAs quantum well heterostructures (QWH) during high-temperature anneals by an initial low-temperature "blocking'' Zn diffusion. Room-temperature photoluminescence measurements of the increase in the lowest electron-to-heavy-hole transition energy in the QW are used to characterize the extent of layer intermixing. Doped (C and Si) samples annealed (850 °C, 12 h) after a low-temperature blocking Zn diffusion (480 °C) exhibit reductions in energy shift from ∼177 meV to as little as ∼18 meV. Similar effects are also observed, but to a lesser extent, for undoped samples. The improved thermal stability is attributed to a Zn-diffusion induced reduction in the number of column-III vacancies in the active layers and is confirmed by secondary-ion mass spectroscopy measurements. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114356
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of low-temperature annealing on the native oxide of AlxGa1−xAs (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 3880-3885 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Data are presented on the effects of low-temperature (∼540 °C) annealing, with and without an As overpressure, on the native oxide of AlxGa1−xAs formed via water vapor oxidation at elevated temperature (∼425 °C). Auger electron spectroscopy data show the Al to be oxidized while the Ga remains unoxidized after the water vapor oxidation of AlxGa1−xAs. Transmission electron microscopy data show a possible composition or phase change upon annealing with an As overpressure. Electron diffraction data indicate that the as-oxidized AlxGa1−xAs is a combination of four possible phases of Al2O3, η, γ, δ, χ, or AlO(OH). Supporting secondary-ion mass spectrometry data are also presented. Ellipsometer measurements indicate an index of refraction n=1.63 (λ=6328 A(ring)) for the native oxide. Ellipsometer measurements of the oxidized and annealed samples show the creation of a region 300–550 A(ring) thick at the oxide-semiconductor interface with n=2.78–2.93.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354482
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  • 10
    Electronic Resource
    Electronic Resource
    Si incorporation in laser-melted AlxGa1−xAs-GaAs quantum well heterostructures from a dielectric source (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 6174-6178 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Data are presented describing the incorporation of Si in locally laser-melted AlxGa1−xAs-GaAs quantum well heterostructures from a thin-film dielectric source. The composition of the melted material, the effects of the Si source (SiO2 or Si3N4) on impurity incorporation, and the doping behavior are examined via secondary-ion mass spectroscopy, electron dispersion x-ray spectroscopy, transmission electron microscopy, and scanning electron microscopy. The data indicate that upon melting, a (Si)y(AlxGa1−xAs)1−y alloy is formed from which impurity-induced layer disordering may be effected. After annealing the melt region is found to contain crystalline segregates, which are attributed to rapid thermal quenching of the melt. Applications of these results to the fabrication of buried-heterostructure lasers by laser-assisted disordering are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346907
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