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  • 1
    Electronic Resource
    Electronic Resource
    Effects of annealing ambient on the electrical properties in heavily C-doped p+-AlGaAs (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 4975-4977 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thermal behavior of the carrier concentration and the lattice constant in heavily carbon-doped p+-AlGaAs epilayers grown by metalorganic chemical vapor deposition are dramatically dependent on the annealing ambient at temperatures between 500 and 700 °C. Annealing in a hydrogen and arsine mixed gas ambient decreases the carrier concentration and increases the lattice constant. On the other hand, annealing in a hydrogen gas ambient increases the carrier concentration and decreases the lattice constant between 500 and 600 °C, which is consistent with our previous data for annealing in a nitrogen gas ambient. However, the carrier concentration after annealing at 700 °C is a little lower in hydrogen than in nitrogen. The above behavior of the carrier concentration and the lattice constant is well explained by incorporating and removing the hydrogen atoms in the epilayers during annealing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352070
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  • 2
    Electronic Resource
    Electronic Resource
    Preparation of a high-Jc Y-Ba-Cu-O film at 700 °C by thermal chemical vapor deposition (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 7948-7950 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A high-Jc Y-Ba-Cu-O superconducting film was successfully prepared at 700 °C on a SrTiO3(100) single-crystal substrate without postannealing by thermal chemical vapor deposition under a low-oxygen partial pressure of 0.036 Torr in the total gas introduced into a hot-wall-type reactor (total gas pressure: 10 Torr), using 1% O2 balanced with Ar as a reactant gas. The sources for the elements of Ba, Y, and Cu were β-diketone metal chelates. The film mainly consisted of YBa2Cu3Ox with c-axis orientation perpendicular to the substrate plane and included small amounts of a-axis oriented and randomly oriented grains. The film showed the superconducting transition temperature defined by zero resistivity at 89 K. The critical current density based on a 2 μV/cm criterion was 2.2 × 106 A/cm2 at 77.3 K and 0 T.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347491
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  • 3
    Electronic Resource
    Electronic Resource
    Estimation of strength distribution of Nb3Sn in multifilamentary composite wire from change in superconducting current due to preloading (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 440-445 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Bronze-processed multifilamentary Nb3Sn superconducting composite wires were loaded and then unloaded at room temperature, resulting in a large change in the critical current (Ic) and the upper critical magnetic field (Hc2) at 4.2 K: the Ic and Hc2 increased, reaching maximum and then decreasing with an increasing applied stress level. The changes in Ic and Hc2 below the loading stress to cause breakage of the Nb3Sn were described well from the viewpoint of the change in residual strain in Nb3Sn. When the applied stress was high enough to cause breakage of the Nb3Sn, the Ic was reduced seriously. From the reduction in Ic in such a case, the strength distribution of Nb3Sn was estimated by using the Weibull distribution function. The result indicated that the shape parameter for the Weibull distribution was 12 and the average strength was 1.02 GPa in the present samples. From the calculation of the residual strain at 4.2 K in combination with the estimated strength distribution of Nb3Sn, the change in Ic at 4.2 K as a function of applied stress at room temperature could be described well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355277
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of post-growth annealing on the recombination centers in C-doped p+-GaAs/n-AlGaAs heterojunctions (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 894-900 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Recombination current in carbon-doped p+-GaAs/n-AlGaAs junction diodes can be reduced by post-growth annealing of the epilayers at 600 and 700 °C but not at 500 °C. The reduction of recombination current at 600 °C under the face-to-face or SiO2 capped condition is by far larger than that under high-AsH3 flow, i.e., arsenic overpressure condition. The reduction can be primarily attributed to the reduction in the 0.55-eV deep levels of recombination centers, which may be an oxygen related complex level with As atoms. The reduction of recombination current at 600 °C is a little smaller when cooling after annealing proceeds slowly, which may be mainly due to around 0.5 eV levels being created during slow cooling. Degradation in the carrier and dopant profiles near junction is not detected even after 700 °C annealing. Annealing at temperatures of 600 °C or higher followed by fast cooling without arsenic overpressure ambient is thus promising for the reduction of recombination centers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349620
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  • 5
    Electronic Resource
    Electronic Resource
    Nondestructive evaluation of channel carrier concentration in modulation-doped InAlAs/InGaAs field-effect transistor structures by room-temperature photoluminescence (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 4333-4340 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The sheet carrier concentration (Ns) of channel layers in modulation-doped InAlAs/InGaAs heterostructure field-effect transistor (HFET) structures with n+InGaAs contact layers has been successfully and nondestructively determined using the room-temperature photoluminescence (PL) method. It is found that the spectral energy width between the maximum position of the main PL peak around 0.8 eV and the half-maximum position on the higher energy side has a good positive linear correlation with the Ns of the channel measured by the van der Pauw method. The scattering of the data is less than ±3×1011 cm−2. The determination of Ns is effective even if the HFET structures have not only n+InGaAs contact layers but also layers for InAlAs Schottky level-shift diodes. From a comparison with low-temperature PL spectra, the main PL peak is attributed to the e2h transition in the quantum well of the channel. It is considered that the slope of the peak stretches further to the high energy as the Fermi energy in the channel become higher, i.e., as the Ns becomes larger. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371366
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  • 6
    Electronic Resource
    Electronic Resource
    Photoluminescence properties of δ-doped barrier layers in modulation-doped InAlAs/InGaAs field-effect transistor structures (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 1696-1703 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A photoluminescence peak from the Si δ-doped InAlAs barrier layers (δ peak) is found around the InAlAs exciton peak from the buffer layer in 15 modulation-doped InAlAs/InGaAs heterostructure field-effect transistor (HFET) structure wafers. The δ peak position ordinarily shifts to shorter wavelength with increasing δ doping concentration. The intensity reduction of the δ peak due to raising the temperature from 6 K is considerably slower than that of the InAlAs exciton peak. The excitation spectrum of the δ peak is clearly different from that of the InAlAs exciton peak and seems to reflect the optical absorption dominated by the potential slope in the upper side of the barrier layer and the quasi-Fermi level. The δ peak is not detected from HFET structures without the contact layers. The δ peak is attributed to the recombination of electrons from the δ-doped layer and photogenerated holes weakly confined in the upper side of the barrier layer. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1338523
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  • 7
    Electronic Resource
    Electronic Resource
    Microscopically inhomogeneous GaAs/InGaP/n+InGaAs epilayer qualities induced by Si implantation and annealing (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 5939-5944 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We investigate the effect of Si ion implantation and subsequent rapid thermal annealing (RTA) on the homogeneity of the crystal quality of metalorganic chemical-vapor-deposited GaAs (150 A(ring))/InGaP (100 A(ring))/n+InGaAs:Si (150–200 A(ring))/GaAs (800 A(ring)) epilayers, which is the structure for heterostructure metal–semiconductor field-effect transistors. It is found that ion implantation to a dose higher than 3×1013 cm−2 at energies between 30 and 90 keV and RTA causes the appearance of dark regions in and near the InGaP layers and the disappearance of the InGaP ordered structure in the lattice images taken with a transmission electron microscope. In the dark regions, the interfaces between the InGaP layer and the GaAs and InGaAs layer become indistinct. An energy-dispersive x-ray analysis shows that compositional atoms intermix through these interfaces. The intermixing seems to be enhanced by implantation damage rather than by the interactions of Si impurities. On the other hand, 1×1013 cm−2 implantation causes no dark regions. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360596
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of an InGaP cap layer on annealing-induced conductivity degradation in heavily Si-doped n+GaAs epilayers (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 1793-1797 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Results are presented on the use of metalorganic chemical-vapor deposition (CVD)-grown InGaP lattice matched to GaAs as part of a capping scheme to protect an n+GaAs epilayer during high-temperature annealing. Such an epilayer structure is important for heterostructure metal-semiconductor field-effect transistors (HMESFETs). It is shown that a surface InGaP layer is more effective than undoped GaAs in preventing conductivity degradation and Si diffusion for an n+GaAs epilayer during high-temperature annealing under plasma-enhanced CVD SiO2 capped condition. In addition, the mechanism of the protective effect is discussed. The results point to the potential applicability of the InGaP for protecting n+GaAs channel epilayers under the gates of HMESFETs during annealing after ion implantation for source/drain ohmic contact or device isolation. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360210
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of oxygen-implant isolation on the recombination leakage current of n-p+ AlGaAs graded heterojunction diodes (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 1892-1894 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The recombination leakage current induced by planar isolation of n-p+AlGaAs graded heterojunction area with oxygen ion implantation followed by annealing at 500–650 °C has been investigated. The recombination leakage current is smaller than that induced by conventional isolation with hydrogen ion implantation; specifically, it is about one order of magnitude smaller after the higher temperature (600–650 °C) annealing. The main origin of the remaining recombination leakage current is probably not oxygen deep levels but rather recombination centers related to the ion implantation damage that remains after annealing. A point-defect complex level, which may be related to the recombination center, is detected at an activation energy of around 0.8 eV by deep level transient spectroscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104003
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  • 10
    Electronic Resource
    Electronic Resource
    Reduction of recombination centers in C-doped p+-GaAs/n-AlGaAs heterojunctions by post-growth annealing (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 934-936 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of post-growth annealing at 500, 600, and 700 °C on the electrical characteristics of C-doped p+-GaAs/n-AlGaAs junction diodes fabricated with metalorganic chemical vapor deposition layers has been investigated. Recombination current is reduced by post-growth annealing at 600 and 700 °C, but not at 500 °C. The current reduction is primarily attributed to the dramatic reduction of 0.55 eV deep levels, which may be oxygen related complex levels. Under present annealing conditions, no degradation of carrier profiles near the p+-n junction is detected. Thus, post-growth annealing at temperatures of 600 °C or higher is a promising method for reducing recombination centers in the C-doped p+-GaAs/n-AlGaAs junction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104482
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