APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

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

8 May 2000

Volume 76, Issue 19, pp. 2647-2800

Return to All Sections
back to top
RSS Feeds

Influence of epitaxial growth and substrate-induced defects on the breakdown of 4H–SiC Schottky diodes

Q. Wahab, A. Ellison, A. Henry, E. Janzén, C. Hallin, J. Di Persio, and R. Martinez

Appl. Phys. Lett. 76, 2725 (2000); http://dx.doi.org/10.1063/1.126456 (3 pages) | Cited 56 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Morphological defects and elementary screw dislocations in 4H–SiC were studied by high voltage Ni Schottky diodes. Micropipes were found to severely limit the performance of 4H–SiC power devices, whereas carrot-like defects did not influence the value of breakdown voltage. The screw dislocation density as determined by x-ray topography analysis under the active area of the diode was also found to directly affect the breakdown voltage. Only diodes with low density of screw dislocations and free from micropipes could block 2 kV or higher. © 2000 American Institute of Physics.
Show PACS
85.30.Kk Junction diodes
85.30.Hi Surface barrier, boundary, and point contact devices
81.15.Kk Vapor phase epitaxy; growth from vapor phase
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.05.Hd Other semiconductors

Low-resistance ohmic contacts to p-type GaN

Y.-L. Li, E. F. Schubert, J. W. Graff, A. Osinsky, and W. F. Schaff

Appl. Phys. Lett. 76, 2728 (2000); http://dx.doi.org/10.1063/1.126457 (3 pages) | Cited 47 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The specific contact resistance of two types of ohmic contacts to p-type GaN is analyzed. First, an ohmic contact formed by a metal electrode deposited on a highly doped p-type GaN layer. Second, an ohmic contact formed by a metal electrode deposited on a thin GaN layer with an internal electric field caused by polarization effects. It is shown that contacts mediated by polarization effects can result, for typical materials parameters, in low contact resistances comparable or better than contacts mediated by dopant-induced surface fields. A type of contact is proposed and demonstrated. These contacts employ polarization charges to enhance tunneling transport as well as high doping. Experimental results on Ni contacts to p-type AlxGa1−xN/GaN doped superlattices are presented. The contacts have linear current–voltage characteristics with contact resistances of 9.3×10−4 Ω cm2, as inferred from linear transmission-line method measurements. The influence of annealing at temperatures ranging from 400 to 500 °C on the contact resistance is studied. © 2000 American Institute of Physics.
Show PACS
73.40.Ns Metal-nonmetal contacts
84.32.Dd Connectors, relays, and switches
73.40.Cg Contact resistance, contact potential
61.72.Cc Kinetics of defect formation and annealing

Fabricating conductive microstructures by direct electron-beam writing on hydrogenated n-type Si-doped GaAs

S. Silvestre, E. Constant, D. Bernard-Loridant, and B. Sieber

Appl. Phys. Lett. 76, 2731 (2000); http://dx.doi.org/10.1063/1.126458 (3 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study the changes in electronic properties of Si-doped GaAs epilayers exposed to a hydrogen plasma and then submitted to electron beams of 20 keV injection energy. Using Hall-effect measurements, we have observed the formation of Si–H complexes and their dissociation due to the electron-beam irradiation. As this last effect increases the conductivity of the epilayer, we have been able to fabricate, with an electron-beam lithography system, various conductive microstructures. Characterizations have been achieved by cathodoluminescence (CL) imaging. Actually, due to the CL reading method which has been used, we have only fabricated micronic-size structures. However, taking into account the high spatial resolution of electron-beam writing, such a process could, possibly, be used as a way of fabrication of mesoscopic structures. © 2000 American Institute of Physics.
Show PACS
85.40.Hp Lithography, masks and pattern transfer
72.20.Fr Low-field transport and mobility; piezoresistance
72.80.Ey III-V and II-VI semiconductors
73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
73.25.+i Surface conductivity and carrier phenomena
78.60.Hk Cathodoluminescence, ionoluminescence

Temperature dependence of the iron donor level in silicon at device processing temperatures

H. Kohno, H. Hieslmair, A. A. Istratov, and E. R. Weber

Appl. Phys. Lett. 76, 2734 (2000); http://dx.doi.org/10.1063/1.126459 (3 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Iron depth profiles in a p-type silicon epitaxial layer on a p+-type silicon substrate have been examined by deep-level transient spectroscopy and computer simulations. By comparing the experimental results with the simulations, we revealed the position of the iron deep donor level to be 0.42±0.04 eV from the valence-band edge at 412–580 °C, which is in a device processing temperature range. The iron donor level was nearly temperature independent within error. Knowing the temperature dependence of the iron donor level at the device processing temperatures, we can design iron gettering in silicon more precisely. © 2000 American Institute of Physics.
Show PACS
71.55.Cn Elemental semiconductors
61.72.Yx Interaction between different crystal defects; gettering effect

Magnetotransport studies of AlGaN/GaN heterostructures grown on sapphire substrates: Effective mass and scattering time

T. Wang, J. Bai, S. Sakai, Y. Ohno, and H. Ohno

Appl. Phys. Lett. 76, 2737 (2000); http://dx.doi.org/10.1063/1.126460 (3 pages) | Cited 27 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Temperature-dependent magnetotransport measurements have been carried out on high-quality two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures with different Al content grown on sapphire substrates. The GaN electron effective mass and the quantum scattering time are determined by well-resolved Shunbikov–de Hass oscillations. The electron effective mass is determined to be 19m0. The ratio of the classic scattering time to the quantum scattering time increases with increasing 2DEG sheet carrier density, which agrees very well with the previous calculation based on an ideal 2DEG in conventional semiconductor systems. Our result indicates that a low density of deep centers results in the much higher mobility of our structure compared with other reports, which is of critical importance in fabricating a high-quality 2DEG structure in AlGaN/GaN systems. © 2000 American Institute of Physics.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.61.Ey III-V semiconductors
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
72.20.My Galvanomagnetic and other magnetotransport effects
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
72.20.Fr Low-field transport and mobility; piezoresistance
73.50.Dn Low-field transport and mobility; piezoresistance

Highly electrically conductive indium–tin–oxide thin films epitaxially grown on yttria-stabilized zirconia (100) by pulsed-laser deposition

Hiromichi Ohta, Masahiro Orita, Masahiro Hirano, Hiroaki Tanji, Hiroshi Kawazoe, and Hideo Hosono

Appl. Phys. Lett. 76, 2740 (2000); http://dx.doi.org/10.1063/1.126461 (3 pages) | Cited 76 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Highly electrically conductive indium–tin–oxide thin films were epitaxially grown on an extremely flat (100) surface of yttria-stabilized zirconia single-crystal substrates at a substrate temperature of 600 °C by a pulsed-laser deposition technique. A resistivity down to 7.7×10−5 Ω cm was reproducibly obtained, maintaining optical transmission exceeding 85% at wavelengths from 340 to 780 nm. The carrier densities of the films were enhanced up to 1.9×1021 cm−3, while the Hall mobility showed a slight, almost linear, decrease from 55 to 40 cm2 V−1 s−1 with increasing SnO2 concentration. The low resistivity is most likely the result of the good crystal quality of the films. © 2000 American Institute of Physics.
Show PACS
81.15.Fg Pulsed laser ablation deposition
68.55.-a Thin film structure and morphology
73.61.Le Other inorganic semiconductors
78.66.Li Other semiconductors
72.80.Jc Other crystalline inorganic semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)

Electronic transport mechanisms of nonalloyed Pt Ohmic contacts to p-GaN

Ja-Soon Jang and Tae-Yeon Seong

Appl. Phys. Lett. 76, 2743 (2000); http://dx.doi.org/10.1063/1.126462 (3 pages) | Cited 43 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the electronic transport mechanisms for nonalloyed Pt Ohmic contacts to p-GaN which were surface treated using a buffered oxide etch solution and (NH4)2Sx. Measurements show that the value of the effective Richardson constant (A∗∗) is 12 A cm−2 K−2, which is considerably smaller than the theoretical value of 103.8 A cm−2 K−2. Based on Hall-effect results, the two-step surface-treated contact is modeled to consist of a Pt/p+-/p-GaN structure, and the conventionally treated contact consists of a Pt/p-GaN structure. The theoretical results obtained using these models are compared with the experimental data. It is shown that for the conventionally treated contact thermionic emission dominates the current flow, whereas for the two-step surface-treated contact, field emission is dominant. © 2000 American Institute of Physics.
Show PACS
73.40.Ns Metal-nonmetal contacts
81.05.Ea III-V semiconductors
73.40.Cg Contact resistance, contact potential
79.40.+z Thermionic emission
79.70.+q Field emission, ionization, evaporation, and desorption
81.65.Cf Surface cleaning, etching, patterning
72.20.My Galvanomagnetic and other magnetotransport effects
85.30.De Semiconductor-device characterization, design, and modeling

Influence of strain relaxation of the AlxGa1−xN barrier on transport properties of the two-dimensional electron gas in modulation-doped AlxGa1−xN/GaN heterostructures

B. Shen, T. Someya, and Y. Arakawa

Appl. Phys. Lett. 76, 2746 (2000); http://dx.doi.org/10.1063/1.126463 (3 pages) | Cited 37 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Influences of the thickness of the Si-doped n-type Al0.22Ga0.78N barrier and the thickness of the Al0.22Ga0.78N spacer on mobility and density of the two dimensional electron gas (2DEG) in modulation-doped Al0.22Ga0.78N/GaN heterostructures were investigated. 2DEG mobilities of 1274 cm2/V s at 300 K and 4495 cm2/V s at 77 K were reached. Both 2DEG mobility and density decrease dramatically when the Al0.22Ga0.78N barrier becomes partially relaxed, indicating that transport properties of the 2DEG are influenced significantly by the piezoelectric polarization of the Al0.22Ga0.78N layer. From our results, the critical thickness of an Al0.22Ga0.78N layer on GaN is estimated to be between 65 and 75 nm, which is much higher than that predicted by theoretical calculation. This may be attributed to the interaction of misfit dislocations and the presence of a high density of extended defects in the Al0.22Ga0.78N layer. © 2000 American Institute of Physics.
Show PACS
73.61.Ey III-V semiconductors
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Dn Low-field transport and mobility; piezoresistance
68.60.Bs Mechanical and acoustical properties
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances
61.72.Nn Stacking faults and other planar or extended defects
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close