jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

1 Dec 1985

Volume 58, Issue 11, pp. 3947-4483

Page 3 of 4 Pages Previous Page Next Page | Jump to Page

Ar ion beam and CCl4 reactive ion etching: A comparison of etching damage and of damage passivation by hydrogen

X. C. Mu, S. J. Fonash, B. Y. Yang, K. Vedam, A. Rohatgi, and J. Rieger

J. Appl. Phys. 58, 4282 (1985); http://dx.doi.org/10.1063/1.335513 (10 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
Damage produced in single‐crystal silicon by two distinctly different dry etching techniques, Ar ion beam etching and CCl4 reactive ion etching is characterized and compared using spectroscopic ellipsometry, reflected high‐ energy electron diffraction, and current‐voltage (I‐V) characteristics of Au contacts to the etched Si. Secondary ion mass spectroscopy is also used to further characterize the CCl4 exposed samples. The effectiveness of low‐energy hydrogen ion implants in passivating this dry etching induced damage is explored. The restoration of I‐V characteristics caused by H+ implants is correlated with the evolution of the spectroscopic ellipsometry, reflected high‐ energy electron diffraction, and secondary ion mass spectroscopy data.
Show PACS
81.65.-b Surface treatments
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
73.20.Hb Impurity and defect levels; energy states of adsorbed species
73.40.Ns Metal-nonmetal contacts

Effects of heat treatment on the composition and semiconductivity of electrochemically deposited CdTe films

Makoto Takahashi, Kohei Uosaki, Hideaki Kita, and Yoshikazu Suzuki

J. Appl. Phys. 58, 4292 (1985); http://dx.doi.org/10.1063/1.335514 (4 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
Effects of heat treatments on crystalline diameter, composition, and semiconductivity of CdTe films deposited electrochemically at −0.35 V (vs Ag/AgCl) from an acidic solution containing 1‐M CdSO4 and 1‐mM TeO2 were studied. As‐grown films contained free Te in addition to CdTe. The intensity of x‐ray diffraction peaks due to CdTe became stronger by the heat treatment at higher temperatures but x‐ray diffraction peak due to metallic Te disappeared at the films annealed above 350 °C in a He atmosphere. The intensity of Auger peaks due to Cd increased and that due to Te decreased by increasing the annealing temperature. The composition of the films annealed above 350 °C was close to that of pure CdTe. The similar effects were observed at the films annealed at 350 °C for various heat treatment periods in a He atmosphere. The change of semiconductivity of the films from p to n type was observed at the films annealed at enough high temperatures and for enough long time. The disappearance of free Te from the films was explained in terms of the temperature dependence of vapor pressure of Te2 from CdTe and metallic Te.
Show PACS
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors
81.40.Rs Electrical and magnetic properties related to treatment conditions
68.55.-a Thin film structure and morphology

Properties of Al/p‐CdTe Schottky barriers

T. L. Chu, Shirley S. Chu, and S. T. Ang

J. Appl. Phys. 58, 4296 (1985); http://dx.doi.org/10.1063/1.335515 (4 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
Al/p‐CdTe Schottky barriers diodes were prepared from the Te (111) face of lightly doped p‐type CdTe single crystals. The characteristics of the diodes have been found to depend strongly on the surface preparation of CdTe. The current‐voltage characteristics of diodes prepared from Br2‐CH3OH etched surfaces are dominated by the tunneling mechanism with high saturation current densities. The use of Br2‐CH3OH etch followed by heating in hydrogen has pronounced effects on the diode quality factor and saturation current densities due to the restoration of the surface stoichiometry. The C‐V measurements at 1 and 10 MHz indicate that Schottky diodes prepared from Br2‐CH3OH etched and 450 °C hydrogen‐annealed CdTe have a barrier height of 0.76 V and that diodes prepared from Br2‐CH3OH etched or lower‐temperature hydrogen‐annealed CdTe show larger barrier heights. In latter cases, the barrier height appears to be controlled by the metal‐semiconductor interface states. In Al/p‐CdTe Schottky barriers with low interface state density, the temperature dependence of the saturation current density suggests that diffusion is the dominant mechanism of current transport, due presumably to the low carrier density in CdTe.
Show PACS
73.30.+y Surface double layers, Schottky barriers, and work functions
85.30.Hi Surface barrier, boundary, and point contact devices

Charge transport and trapping in silicon nitride‐silicon dioxide dielectric double layers

S. Manzini and F. Volonté

J. Appl. Phys. 58, 4300 (1985); http://dx.doi.org/10.1063/1.336285 (7 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Time, electric field, and temperature dependence of the flat‐band voltage shift in polysilicon‐silicon nitride‐(thick) silicon dioxide‐silicon capacitors subjected to high field stress has been studied in this paper. A ‘‘turn around’’ effect in the behavior of the flat‐band voltage shift versus time is observed, both in the accumulation and in the strong inversion mode, in the full range of temperatures investigated (77 K≤T≤453 K). Early time charge trapping seems to be dominated by transport of carriers, holes or electrons injected at the gate electrode, in the nitride layer. A Poole–Frenkel‐active trap for holes is determined to be located at 1.0 eV above the nitride valence‐band edge and a Poole‐Frenkel‐active trap for electrons 1.3 eV below the nitride conduction‐band edge. The dark contact current‐contact field characteristics at the silicon‐silicon dioxide interface are obtained at room temperature for both gate bias conditions. The contact current for positive gate voltage J+ox appears to be dominated by tunneling (Fowler–Nordheim) emission of electrons from the silicon substrate. The contact current for negative gate voltage J−ox is several orders of magnitude smaller than J+ox and is tentatively attributed to tunneling (Fowler–Nordheim) emission of holes from the silicon substrate. The estimated tunneling barrier height for holes is ϕh0 =4.4±0.1 eV.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors

Optical studies of impurity trapping at the GaAlAs/GaAs interface in quantum well structures

M. H. Meynadier, J. A. Brum, C. Delalande, M. Voos, F. Alexandre, and J. L. Liévin

J. Appl. Phys. 58, 4307 (1985); http://dx.doi.org/10.1063/1.335516 (6 pages) | Cited 35 times

Full Text: | Download PDF

Show Abstract
We present low‐temperature photoluminescence studies of nominally undoped GaAs quantum wells in which weak acceptor‐related emissions can be observed. We investigate the influence of different sequences of prelayers, in which the number and the aluminum concentration of the layers are varied, on the impurity concentration in the quantum well, and show that thin layers of low aluminum percentage act as very efficient impurity trapping centers. We also present calculations of the electron to acceptor photoluminescence line shape, which show that the acceptor distribution has its maximum at the well interface, extending about 7 Å in the barrier and 12 to 30 Å in the well.
Show PACS
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients

Liquid‐phase epitaxial growth and characterization of low carrier concentration n‐ and p‐type In0.53Ga0.47As

Mulpuri V. Rao

J. Appl. Phys. 58, 4313 (1985); http://dx.doi.org/10.1063/1.335517 (4 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
Both n‐ and p‐type In0.53Ga0.47As layers with low carrier concentrations (∼1015 cm−3) were achieved reproducibly by adding Zn‐doped GaAs to the liquid‐phase epitaxial growth melt. The distribution coefficient of Zn in In0.53Ga0.47As (kZn) is found to be 0.52±0.08. Analysis of hole mobility data in the temperature range 10–300 K has revealed that the combination of nonpolar‐optical‐phonon and acoustic‐deformation‐potential scattering mechanisms play a more significant role in the high‐temperature range. Photoluminescence measurements were also performed on the ternary layers.
Show PACS
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors
78.40.Fy Semiconductors
68.55.-a Thin film structure and morphology
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients

Tellurium and zinc doping in In0.5Ga0.5P grown by liquid‐phase epitaxy

M.C. Wu, Y. K. Su, C. Y. Chang, and K. Y. Cheng

J. Appl. Phys. 58, 4317 (1985); http://dx.doi.org/10.1063/1.335518 (5 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
In0.5Ga0.5P epitaxial layers doped with Te and Zn were grown on (100) GaAs substrates by liquid‐phase epitaxy using a supercooling method. The lattice mismatch between the InGaP layer and the GaAs substrate decreases with increasing Te or Zn impurity concentration. The electrical properties of doped layers were determined by Hall measurements at 300 and 77 K. Room‐temperature carrier concentrations ranging from 2×1017 to 3×1018 cm−3 for n‐type and from 2×1017 to 2×1019 cm−3 for p‐type dopants were obtained reproducibly. The full width at half maximum value of the 300 K photoluminescent spectrum increases with carrier concentration for both Te‐ and Zn‐doped layers. The relative intensity of the 300 K photoluminescent peak increases with electron concentrations up to 3×1018 cm−3 for Te‐doped layers, but it presents a maximum value at 1×1018 cm−3 for Zn‐doped layers. The 14 K photoluminescent spectra show three distinctive peaks and their relative intensities change with hole concentrations. Finally, the relationship between the acceptor ionization energy and hole concentration is described.
Show PACS
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors
75.20.Ck Nonmetals
68.55.-a Thin film structure and morphology
61.72.U- Doping and impurity implantation

Design of improved integrated thin‐film planar dc SQUID gradiometers

M. B. Ketchen

J. Appl. Phys. 58, 4322 (1985); http://dx.doi.org/10.1063/1.335519 (4 pages) | Cited 24 times

Full Text: | Download PDF

Show Abstract
Key issues in the design of improved first and second derivative, thin‐film, planar dc SQUID gradiometers are discussed. The introduction of a planar coupling scheme to optimally couple the planar dc SQUID to the gradiometer pickup loops leads to significantly increased sensitivity as well as elimination of the sensitivity differences between series and parallel gradiometer loop configurations. Two‐hole and figure‐8 SQUID designs are presented which are consistent with intrinsic gradiometer balance ≲10−4 against uniform field changes. Straightforward calculations together with data from existing low‐noise SQUIDs suggest improvements in gradient sensitivity on the order of 102 over existing planar gradiometers.
Show PACS
85.25.-j Superconducting devices

Magnetic response of type‐II superconductors subjected to large‐amplitude parallel magnetic fields varying in both magnitude and direction

Antonio Perez‐Gonzalez and John R. Clem

J. Appl. Phys. 58, 4326 (1985); http://dx.doi.org/10.1063/1.335520 (10 pages) | Cited 27 times

Full Text: | Download PDF

Show Abstract
Starting from our general critical‐state theory, which includes the effects of both flux‐line cutting and flux pinning, we develop a numerical method for finding the magnetic response of type‐II superconductors subjected to parallel magnetic fields that change in both magnitude and orientation. We describe model calculations of the time‐evolving magnetic profiles when the direction of an applied magnetic field of fixed magnitude oscillates with large amplitude, and we compare our results with related experiments by Cave and LeBlanc. We also report model calculations for the ac behavior when the sample is subjected to a dc bias field and a large‐amplitude ac field at various angles (0°, 45°, and 90°) relative to this field.
Show PACS
74.25.N- Response to electromagnetic fields
74.25.-q Properties of superconductors

Experimental evidence of a multiphase magnetic system in fine particles of ferric hydroxysulfate

P. C. Morais and K. Skeff Neto

J. Appl. Phys. 58, 4336 (1985); http://dx.doi.org/10.1063/1.335521 (6 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Magnetization data obtained by a microvibrating sample magnetometer are presented. These data are obtained at different values of an external field applied to a sample which shows a bimodal particle‐size distribution. The bendings in the M3×T plot are taken as an evidence of magnetic reorderings. These magnetic reorderings are discussed extensively.
Show PACS
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Kj Amorphous and quasicrystalline magnetic materials
75.30.Cr Saturation moments and magnetic susceptibilities

Raman study of GaAs‐InxAl1−x As strained‐layer superlattices

M. Nakayama, K. Kubota, T. Kanata, H. Kato, S. Chika, and N. Sano

J. Appl. Phys. 58, 4342 (1985); http://dx.doi.org/10.1063/1.335522 (4 pages) | Cited 22 times

Full Text: | Download PDF

Show Abstract
Raman spectroscopy has been used to study the lattice‐mismatch strains in GaAs‐InxAl1−xAs strained‐layer superlattices grown by molecular beam epitaxy with the layer thicknesses of 10–200 Å and In content x of 0.11, 0.20, and 0.35. The strain‐induced shifts of the longitudinal optic phonon modes indicate that the GaAs and InxAl1−xAs layers have the tensile and compressive strains, respectively, along the interfaces. The strain calculated from the observed frequency shift agrees with the lattice‐mismatch strain given by the elastic theory.
Show PACS
78.30.Hv Other nonmetallic inorganics
68.55.-a Thin film structure and morphology
68.35.Gy Mechanical properties; surface strains
68.35.Iv Acoustical properties

Mechanisms of electroluminescence during aging of polyethylene

C. Laurent, C. Mayoux, and S. Noel

J. Appl. Phys. 58, 4346 (1985); http://dx.doi.org/10.1063/1.335523 (8 pages) | Cited 17 times

Full Text: | Download PDF

Show Abstract
The study of electrical aging of polyethylene subjected to a 50 Hz ac voltage has shown that electroluminescence occured in the bulk of the polymer. These light emissions (detected in the visible range of wavelength) were due to the buildup of space charge around the electrodes. In a previous paper [J. Appl. Phys. 54, 1532 (1983)] results concerning the role of dissolved gases in polyethylene were presented, where particular attention was paid to electroluminescence effects. The present work aims to answer the two following questions: (1) what are the mechanisms causing the electroluminescence? (2) what is the nature of the luminescent centers? Study of the light emission with respect to the applied voltage form, the frequency, (when ac voltage is applied) and the voltage amplitude, shows that the light emission is due to radiative recombinations of carriers injected through the metal‐dielectric interface following the Fowler–Nordheim effect. This process requires a double injection of carriers. The influence of electrode material on the light emission intensity is then shown, which is in good agreement with the injection mechanism proposed. The luminescent centers are carriers stabilized by deep traps in the polyethylene.
Show PACS
81.40.Tv Optical and dielectric properties related to treatment conditions
78.60.Fi Electroluminescence
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
77.22.Jp Dielectric breakdown and space-charge effects

Transient cathodoluminescence of semiconductors in a scanning electron microscope

A. Jakubowicz

J. Appl. Phys. 58, 4354 (1985); http://dx.doi.org/10.1063/1.335524 (6 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
A theoretical analysis of the cathodoluminescence versus time decay is presented when the electron beam in a scanning electron microscope is turned off. It is shown that the initial part of the decay depends on the surface recombination velocity, the absorption coefficent, and the range of primary electrons. At longer times after the cutoff of the electron beam, the decay approaches a near‐exponential behavior, which is controlled only by the bulk lifetime.
Show PACS
78.60.Hk Cathodoluminescence, ionoluminescence

Optical and electronic properties of the electron beam resist poly(butene‐1‐sulfone)

M. W. Williams, D. W. Young, J. C. Ashley, and E. T. Arakawa

J. Appl. Phys. 58, 4360 (1985); http://dx.doi.org/10.1063/1.335525 (5 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
The optical properties of thin films of poly(butene‐1‐sulfone), PBS, an electron beam resist, are presented for the range of photon energies from 2.5 to 39.0 eV. The density of these films is found to be (1.39 ± 0.02) g cm−3. A sum‐rule calculation is used to demonstrate the overall consistency of the data obtained. The optical data are used to calculate inelastic electron mean‐free paths in PBS as a function of incident electron energy from 100 to 10 000 eV.
Show PACS
75.20.Ck Nonmetals
73.61.Ng Insulators
61.85.+p Channeling phenomena (blocking, energy loss, etc.)

A new correction to Schottky barrier lowering in cathodes

Genghmun Eng

J. Appl. Phys. 58, 4365 (1985); http://dx.doi.org/10.1063/1.335526 (9 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
A new technique is developed for approximating cathode current‐voltage (I‐V) and current‐temperature (I‐T) characteristics in a planar diode configuration. For a uniform work function surface, this method allows both for space‐charge effects and for Schottky barrier lowering. Using this method, we derive an explicit first correction to the Schottky effect: ΔΦnew =ΔΦ0[1−(Jnet/JC)]1/2, where ΔΦ0 is the standard Schottky barrier lowering (eV), Jnet is the net emission current density, and JC is the Child’s law current density. The following closed form expression then approximates the net emission current density: Jnet≂JC (JR>JC), and Jnet≂JR exp(ΔΦnew/kT) (JR<JC), where JR is the Richardson’s current density. This equation for Jnet connects the space‐charge‐limited (SCL) emission regime to the deep temperature‐limited (TL) regime. The SCL‐to‐TL transition point is found to be JR, and the above equations for emission current are continuous with a continuous slope at the transition point.
Show PACS
73.30.+y Surface double layers, Schottky barriers, and work functions
79.40.+z Thermionic emission

A model for pulsed laser melting of graphite

J. Steinbeck, G. Braunstein, M. S. Dresselhaus, T. Venkatesan, and D. C. Jacobson

J. Appl. Phys. 58, 4374 (1985); http://dx.doi.org/10.1063/1.335527 (9 pages) | Cited 43 times

Full Text: | Download PDF

Show Abstract
A model for laser melting of carbon at high temperatures to form liquid carbon has been developed. This model is solved numerically using experimental data from laser irradiation studies in graphite consistent with a melting temperature for graphite of 4300 K. The parameters for high‐temperature graphite are based on the extension of previously measured thermal properties into the high‐temperature regime. A simple classical free electron gas model is used to calculate the properties of liquid carbon. There is very good agreement between the model calculation and experimental results for laser pulse fluences below 2.0 J/cm2. Modifications to the model for larger laser pulse fluences are discussed.
Show PACS
64.70.D- Solid-liquid transitions
68.08.-p Liquid-solid interfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
05.70.-a Thermodynamics
72.15.Cz Electrical and thermal conduction in amorphous and liquid metals and alloys

An analysis of dislocation reduction by impurity hardening in the liquid‐encapsulated Czochralski growth of 〈111〉 InP

A. S. Jordan, G. T. Brown, B. Cockayne, D. Brasen, and W. A. Bonner

J. Appl. Phys. 58, 4383 (1985); http://dx.doi.org/10.1063/1.335528 (7 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Excessive impurity additions have been widely used to suppress dislocation generation in the liquid‐encapsulated Czochralski (LEC) growth of InP. We have analyzed this approach by means of the quasi‐steady‐state heat transfer/thermal stress model. A strong motivation for the investigation was provided by the recent measurement of the critical resolved shear stress σCRS of InP as a function of temperature in the range 748–948 °K for several Ge and S concentrations. The experimental data were analyzed by the method of least squares via the usually accepted logarithmic dependence of σCRS on reciprocal temperature. The extrapolated values of σCRS exhibit a monotonic increase with impurity addition at temperatures near the melting point. Introducing the σCRS and realistic estimates of other physical properties (thermal diffusivity, thermal expansion coefficient, elastic constants, etc.) in the thermal stress model, the dislocation distribution pattern in a {111} substrate cut from a 〈111〉 boule was constructed. This necessitated a suitable recasting of the formalism that was previously applicable only to the {100} orientation. The computed dislocation contour maps on {111} wafers display sixfold symmetry resembling the ‘‘Star of David,’’ in overall agreement with etch‐pit patterns. InP crystals 2.5 cm in diameter grown in a standard high ambient temperature gradient but containing a large amount of Ge (≂1019 cm−3) are predicted and observed to be dislocation‐free. On the other hand, in nominally undoped material a large density of defects is forecast, especially at the periphery, in line with the etchpit configuration. Intermediate doping levels (∼1017 cm−3 Ge, ∼1018 cm−3 S) reduce the density in the core but leave the outer edge essentially unaltered.
Show PACS
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients

Hole transport equation analysis of photoelectrochemical etching resolution

F. W. Ostermayer, P. A. Kohl, and R. M. Lum

J. Appl. Phys. 58, 4390 (1985); http://dx.doi.org/10.1063/1.335529 (7 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
A theoretical model that predicts the spatial resolution for grating formation on n‐type semiconductors by photoelectrochemical etching has been developed. The ratio of the amplitude of the grating to the average depth etched by a sinusoidal spatial variation of light intensity was determined from a model that takes into account the drift and two‐dimensional diffusion of the photogenerated holes and their rate of reaction at the surface. Experimental measurements of the growth of gratings agree with the predictions of the theory for the dependence on the period of the grating, the carrier concentration of the semiconductor, and the wavelength of the light. Fitting the experimental data to the theory provides a novel method for determining the reaction velocities of the decomposition reaction in different electrolytes. The theory predicts that large improvements in the resolution would be possible if electrolytes giving higher reaction velocities could be found.
Show PACS
42.79.Dj Gratings
81.65.-b Surface treatments
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

UV‐laser photolysis of trimethylaluminum for Al film growth

T. Motooka, S. Gorbatkin, D. Lubben, and J. E. Greene

J. Appl. Phys. 58, 4397 (1985); http://dx.doi.org/10.1063/1.335530 (5 pages) | Cited 21 times

Full Text: | Download PDF

Show Abstract
The photodissociation of dimerized trimethylaluminum, Al2(CH3)6, (TMA) by KrF laser irradiation (248 nm, 5 eV) has been investigated. Optical spectroscopy was used to measure the emission intensities I of excited photofragments as a function of TMA pressure P. The intensities of neutral Al atoms and CH radicals were observed to have quite different pressure dependencies indicating that they were formed by different mechanisms. IAl and ICH initially increased linearly with increasing pressure, however IAl saturated at P≂0.6 Torr (80 Pa) while ICH reached a maximum at P≂0.01 Torr (1.33 Pa) and then decreased with further increases in pressure. Based upon the experimental results and molecular orbital calculations, a model was proposed for the photolysis of TMA. The primary conclusions were that Al atoms were formed directly by a cascade process initiated by a single‐photon absorption while CH radicals were generated through a chemical reaction between photofragments. An analysis of the steps involved in the cascade process suggests that it should be possible to grow high‐purity, essentially C‐free, Al films by photodecomposition of TMA in ultrahigh vacuum in agreement with preliminary experiments.
Show PACS
82.50.Hp Processes caused by visible and UV light
32.50.+d Fluorescence, phosphorescence (including quenching)
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.-a Thin film structure and morphology

Characterization of high‐efficiency silicon solar cells

M. A. Green, A. W. Blakers, and C. R. Osterwald

J. Appl. Phys. 58, 4402 (1985); http://dx.doi.org/10.1063/1.336286 (7 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
Preliminary results on silicon solar cells of improved performance recently have been described. The present paper describes the results of a more detailed optical and electrical characterization of these devices. The high performance of the cells is shown to be due to a high optical efficiency and near ideal junction characteristics combined with low parasitic resistance losses.
Show PACS
84.60.Jt Photoelectric conversion
85.30.De Semiconductor-device characterization, design, and modeling
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
85.60.Dw Photodiodes; phototransistors; photoresistors

The effects of hydrogen in sealed electrical contacts

Rudolf Schubert and Eoin W. Gray

J. Appl. Phys. 58, 4409 (1985); http://dx.doi.org/10.1063/1.335531 (6 pages)

Full Text: | Download PDF

Show Abstract
Hydrogen has been an integral atmospheric component of sealed electrical contacts for decades because of its effect on reliability. It is well known that hydrogen is a needed component to prevent high contact resistance due to carbon‐spot formation. This hydrogen benefit has been attributed to hydrogenation of hydrocarbons (HC), enhanced volatilization of previously deposited carbon, enhanced catalytic activity, and thermal cooling. By a variety of physical and chemical laboratory techniques, this paper shows that the hydrogen is not itself directly active. However, some of the hydrogen is converted to water during the glass sealing process. It is this water which plays the active role in the process of quenching carbon formation from hydrocarbon impurities and also acts as a diluent of HC’s adsorbed on the contact surface and in the arcing volume. This limits the carbon accumulation on the contacts and increases lifetime reliability.
Show PACS
84.32.Dd Connectors, relays, and switches
73.40.-c Electronic transport in interface structures

An extremely sensitive heterostructure for parts per million detection of hydrogen in oxygen

S. J. Fonash, Zheng Li, and M. J. O’Leary

J. Appl. Phys. 58, 4415 (1985); http://dx.doi.org/10.1063/1.335532 (5 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
The fabrication and performance of a new type of solid‐state hydrogen detector is described. This device is extremely sensitive at room temperature to parts per million of hydrogen in the interesting situation of an oxygen‐rich ambient. The device is a heterostructure whose key layer is a TiOx film produced by low‐pressure chemical vapor deposition. Due to the presence of this layer, the device switches from one conduction state in oxygen to another in a hydrogen‐rich ambient. This transition from one state to the other is a function of the ambient hydrogen concentration and is caused by the evolution of a barrier in the TiOx layer.
Show PACS
85.30.De Semiconductor-device characterization, design, and modeling
82.47.-a Applied electrochemistry
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
82.80.-d Chemical analysis and related physical methods of analysis

Role of short‐circuiting pathways in reduced ZnO varistors

E. Sonder, Lionel M. Levinson, and W. Katz

J. Appl. Phys. 58, 4420 (1985); http://dx.doi.org/10.1063/1.335533 (6 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Electrical measurements and secondary ion mass spectrometry (SIMS) observations have been made to elucidate the mechanisms involved in the degradation of ZnO varistors at elevated temperatures in reducing atmospheres. The electrical measurements indicate that the degradation sensitivity depends to some extent on varistor composition but can be highly variable for different varistors of the same formulation and even within a given varistor sample. The SIMS data indicate that oxygen ions are highly mobile when varistors are heated above 290 °C, and it is proposed that flaws, such as microcracks in the varistors, act as conduits for oxygen at elevated temperatures. A circuit model in which a reduced varistor is characterized by short‐circuiting regions around such flaws predicts an electric field versus current density that is similar to that observed in experiments.
Show PACS
84.32.Ff Conductors, resistors (including thermistors, varistors, and photoresistors)
72.80.Ey III-V and II-VI semiconductors

Low‐temperature characteristics of electron ionization rates in (100)‐ and (111)‐oriented InP

Fukunobu Osaka and Takashi Mikawa

J. Appl. Phys. 58, 4426 (1985); http://dx.doi.org/10.1063/1.335534 (5 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
Electron ionization rates α in both (100)‐ and (111)‐oriented InP have been derived at a low‐temperature range between 77 and 293 K from photomultiplication data measured on a mesa‐type (100)‐oriented InP diode and a planar type (111)‐oriented InP diode. It has been found that there is no difference in α between the two orientations in this temperature range. This indicates that the contribution of ballistic electrons to impact ionization is insignificant not only at room temperature but at low temperatures. A Monte Carlo simulation of α in both (100)‐ and (111)‐oriented InP at low temperatures have been carried out for the analysis of the experimental data. The simulated results have been found to agree with the experimental ones fairly well in the considered electric field and temperature ranges. α has been demonstrated to have no orientation dependence and the probability of ballistic electrons to cause impact ionization has been found to be extremely small (about 0.01% at 300 K and 0.05% even at 77 K). No anisotropy in electron ionization rates in InP has been attributed to this very small probability.
Show PACS
79.20.Kz Other electron-impact emission phenomena
85.60.Dw Photodiodes; phototransistors; photoresistors
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.30.De Semiconductor-device characterization, design, and modeling

Charge control and geometric magnetoresistance of a gated AlGaAs/GaAs heterojunction transistor

J. P. Harrang, R. J. Higgins, R. K. Goodall, R. H. Wallis, P. R. Jay, and P. Delescluse

J. Appl. Phys. 58, 4431 (1985); http://dx.doi.org/10.1063/1.335535 (7 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
We have measured a series of low‐temperature transport parameters of AlGaAs/GaAs heterojunction transistors. The techniques used provide direct measurement of the two‐dimensional electron gas on the same sample in which standard device characterization tools are applied. This creates an environment for devising and testing realistic device models. The apparent charge density is measured via both Hall and capacitance‐voltage measurements and is compared with the two‐dimensional electron gas charge measured via Shubnikov–de Haas conductivity oscillations. From this comparison we interpret the charge control of these gated heterojunction devices. Geometric magnetoresistance, magnetotransconductance, and Hall measurements of the mobility are presented and complications arising from the layered structure of the heterojunctions are discussed.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.20.My Galvanomagnetic and other magnetotransport effects
85.30.De Semiconductor-device characterization, design, and modeling
85.30.Tv Field effect devices
Page 3 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close