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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 1565-1569 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have calculated the temperature dependence of the carrier density in epitaxial layers of semiconductors deposited on semi-insulating substrates when the potentials at the surface and the substrate interface are pinned. The results of these calculations are compared to experiments on thin, nominally undoped p-type layers of GaAs deposited epitaxially on EL2-dominated substrates. The theory predicts that as the temperature is lowered to some critical value the depletion layers at the edges of the epilayer overlap for thin, lightly doped samples. Below this value the carrier density decreases exponentially with inverse temperature with an activation energy which depends on the surface and interface potentials, as well as on the dopant concentration and the width of the layer. This activation energy can be derived analytically for strong depletion. In the intermediate range between negligible and complete depletion of the layer the carrier density must be obtained by numerical methods, and we present the results of such a calculation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 5408-5419 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The system consisting of an unintentionally doped GaAs epitaxial layer on a semi-insulating (SI) GaAs substrate forms a starting point for the GaAs integrated circuit technology. It is also the genesis of problems for GaAs field-effect transistors (FETs) in the form of back gating. Potentials applied to a point on the surface may propagate several millimeters to modulate the conduction of an FET built into the layer. In addition, the conductivity of the epilayer may be efficiently modulated by a potential applied to the back of the SI substrate. Well-developed p-channel FET characteristics have been observed in an epilayer on top of a 0.4-mm-thick SI substrate using the back of the substrate as a gate. Numerical simulations revealed that under some circumstances potentials may propagate across the substrate with little attenuation, giving a degree of modulation in agreement with experiment. Conditions for current transport then corresponded closely to those in a rectifying p-n junction. The parameter space was fully explored numerically and using an analytical model, and a simple set of conditions for rectification were developed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 2285-2287 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pseudomorphic (In,Ga)As layers are used in GaAs-based semiconductor-insulator- semiconductor (SIS) structures to shift the threshold voltage from the natural, near-zero value. The threshold voltage is shifted positively for (In,Ga)As gate layers, and negatively for (In,Ga)As channel layers, by the (In,Ga)As/GaAs conduction-band offset. The thermionic and field emission barrier heights agree with shifts obtained in capacitance-voltage characteristics. The structures withstand implant activation anneals, establishing a simple technology to create either enhancement or depletion-mode devices.
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 38 (1973), S. 3175-3179 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 1459-1461 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electrical measurements of n+-GaAs/π-(Al,Ga)As/π-GaAs semiconductor-insulator-semiconductor (SIS) heterostructure capacitors and field-effect transistors (FET's) show that the (Al,Ga)As/GaAs heterojunction abruptness is well preserved for an arsine flash anneal of 1 s at temperatures up to ∼900 °C. The heterostructure stability is also preserved for a low-dose silicon implant across the (Al,Ga)As/GaAs heterojunction and subsequent annealing. Arsenic overpressure is found to be necessary, even for short time annealing, to prevent excessive As loss from a GaAs or (Al,Ga)As surface. High mobility enhance–deplete heterostructure SISFET's with sharp current versus voltage (I-V) turn-on characteristics have been fabricated using ion implantation and arsine flash anneal.
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 2214-2216 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical characteristics of regrown interfaces deposited using an alternate metalorganic chemistry, diethylgallium chloride (DEGaCl), are investigated. With the appropriate HCl pre-regrowth surface treatment, these interfaces are found to be of very high quality with no substantial interface charge. The contact resistivity, as determined by transmission line measurements, is (2–4)×10−7 Ω cm2 at both 77 and 300 K. Secondary-ion mass spectroscopy measurements show no detectable accumulation of impurities at the regrown interface, in contrast to those regrown using the conventional trimethylgallium-based chemistry.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 171-173 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the first realization of extremely low resistivity regrown ohmic contacts to a variety of GaAs/AlGaAs structures using selective epitaxy. For planar regrown n+-GaAs contacts to n-GaAs we have obtained contact resistivity values ∼1×10−7 Ω cm2, and ∼1×10−8 Ω cm2 for lateral contacts to a 10-nm-thick buried n+-GaAs layer. The contact resistances were substantially temperature independent from 77 to 300 K. Regrown contacts to a 2DEG structure exhibited a much higher and temperature-dependent contact resisitivity which could be accounted for (according to numerical simulation) by ∼5×1012 cm−2 traps at the AlGaAs/ regrown GaAs interface. Post-growth annealing of the regrown annealing of the regrown interface drastically reduced the value of contact resistivity for 2DEG structures to ∼2×10−8 Ω cm2.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 1709-1712 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The conduction-band discontinuity (ΔEc) between In0.53Ga0.47As and In0.52Al0.48As is determined by current-voltage measurements on n+-InGaAs/InAlAs/n−-InGaAs capacitors. Current is found to be dominated by thermionic emission conduction down to 180 K. Barrier heights are determined from the slope of ln(J/T2) vs 1/T where good straight-line fits are obtained in the thermionic emission range. After correcting for the Fermi level a conduction-band discontinuity of 0.51±0.04 eV is obtained representing 70% of the total band-gap discontinuity. Furthermore, capacitance-voltage measurements are fit to classical capacitance-voltage theory and show that no charge is present in the InAlAs insulating layer.
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 1302-1313 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The energy distribution of hot electrons in high-field stressed amorphous silicon dioxide (SiO2) films have been measured using a vacuum emission technique. Electrons having average energies (approximately-greater-than)2 eV and an energy relaxation length of λ≈32 A(ring) are observed at all fields studied ((approximately-greater-than) 2 MV/cm). However, contrary to previous theoretical expectations, the majority of carriers in the distribution remains stable at all fields. The results are in agreement with other recent experiments (electroluminescence and carrier separation) which only measure the average energy of hot electrons in SiO2 and with recent Monte Carlo transport calculations which include scattering by both optical and acoustic phonon modes. Results for varying SiO2 thickness, metal gate thickness, oxide composition, and metal gate composition will be discussed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 787-789 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High resolution x-ray diffraction (HRXRD) is proposed as a nondestructive tool for the characterization of the silicon on insulator (SOI) film in bonded wafers. Although the bonded stack may consist of many amorphous layers, the measured diffraction spectra only show the crystalline SOI layer, thus providing a direct measurement of the film. We have demonstrated that HRXRD is capable of accurately measuring the film thickness, the tilt of the film planes with respect to the substrate planes, and the rotation misalignment of the bonded film with respect to the carrier substrate. SOI films with thicknesses down to 30 nm were readily measured with accuracy better than 1%. It is shown that an angular separation between the layer and the substrate diffraction peaks is maintained due to an unintentional miscut which usually exists in the starting wafers used for bonding. This angular separation is unique to bonded wafers as opposed to separation by implanted oxygen (SIMOX) wafers where the layer and substrate peaks are nonseparable. Calculated diffraction spectra based on the kinematic approach showed excellent agreement with the measured diffraction. © 1999 American Institute of Physics.
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