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

17 Nov 1997

Volume 71, Issue 20, pp. 2871-3018

Page 2 of 2 Pages Previous Page | Jump to Page

Microstructures of phased-in Cr–Cu/Cu/Au bump-limiting metallization and its soldering behavior with high Pb content and eutectic PbSn solders

G. Z. Pan, Ann A. Liu, H. K. Kim, K. N. Tu, and Paul A. Totta

Appl. Phys. Lett. 71, 2946 (1997); http://dx.doi.org/10.1063/1.120224 (3 pages) | Cited 23 times

Full Text: | Download PDF

Show Abstract
The microstructure of phased-in Cr–Cu/Cu/Au multilayer thin films and their solderability with high Pb-content PbSn solder (95/5%) and eutectic PbSn solder (37/63%) were studied by using cross-sectional transmission electron microscopy and scanning electron microscopy. We found that the phased-in Cr–Cu layer is intermixed and grains of both Cr and Cu are elongated along the growth direction. This special compositionally graded or functionally graded microstructure presents a lock-in effect of the Cr and Cu grains. It has succeeded in preventing the spalling of Cu3Sn in solder joints formed using the 95/5% solder, but failed in preventing the spalling of Cu6Sn5 in those formed using the eutectic solder. We suggest that the difference may be due to the different dissolution rates of the two compounds in the solders. © 1997 American Institute of Physics.
Show PACS
85.40.Ls Metallization, contacts, interconnects; device isolation
81.20.Vj Joining; welding
68.55.-a Thin film structure and morphology

An analysis technique for extraction of thin film stresses from x-ray data

Guido Cornella, Seok-Hee Lee, William D. Nix, and John C. Bravman

Appl. Phys. Lett. 71, 2949 (1997); http://dx.doi.org/10.1063/1.120225 (3 pages) | Cited 22 times

Full Text: | Download PDF

Show Abstract
We demonstrate a technique for experimentally determining stresses in crystalline thin films without any knowledge of the elastic properties of the thin film material. The results are obtained from interplanar spacing versus sin2 Ψ plots for different stress states. The interplanar spacings are measured by non-symmetric x-ray diffraction. The different stress states are produced by annealing the thin film/substrate samples at elevated temperatures in air and by cooling them in liquid nitrogen. Poisson’s ratio for isotropic films or a similar quantity for anisotropic films can be found through the use of this technique. An extension of this technique also permits the measurement of the coefficient of thermal expansion without removing the film from the substrate. © 1997 American Institute of Physics.
Show PACS
68.60.Bs Mechanical and acoustical properties
65.40.De Thermal expansion; thermomechanical effects
61.05.C- X-ray diffraction and scattering

In-plane aligned Pr6O11 buffer layers by ion-beam assisted pulsed laser deposition on metal substrates

V. Betz, B. Holzapfel, D. Raouser, and L. Schultz

Appl. Phys. Lett. 71, 2952 (1997); http://dx.doi.org/10.1063/1.120226 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
Biaxially aligned praseodymium oxide (Pr6O11) thin films were prepared by ion-beam assisted laser deposition on mechanically polished metal alloy substrates. A low divergence rf plasma source was used as an assisting source. Deposited films showed (001) oriented film growth with a strong biaxial alignment in the film plane. The degree of in-plane orientation dependent on ion-to-atom ratio and ion bombardment angle was studied. Planar ion channeling along the {110} planes is used to explain the observed alignment features. At an ion-to-atom ratio of 0.17 and an ion incident angle of 60°, in-plane orientations of 16° full width at half-maximum were obtained. Due to the low lattice mismatch (0.3%) to YBa2Cu3Ox films, the material could be an alternative to the YSZ/CeO2 buffer layer system currently used for high critical current carrying superconducting tapes. © 1997 American Institute of Physics.
Show PACS
81.15.Fg Pulsed laser ablation deposition
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
74.78.-w Superconducting films and low-dimensional structures

Deposition of in-plane textured MgO on amorphous Si3N4 substrates by ion-beam-assisted deposition and comparisons with ion-beam-assisted deposited yttria-stabilized-zirconia

C. P. Wang, K. B. Do, M. R. Beasley, T. H. Geballe, and R. H. Hammond

Appl. Phys. Lett. 71, 2955 (1997); http://dx.doi.org/10.1063/1.120227 (3 pages) | Cited 134 times

Full Text: | Download PDF

Show Abstract
We report the growth of in-plane textured (100) MgO on amorphous Si3N4 substrates by ion beam assisted deposition (IBAD). The textured MgO can be used as a structural template for subsequent epitaxial thin film deposition. The results are compared with IBAD of (100) and (111) yttria-stabilized-zirconia (YSZ). Based on transmission electron microscopy (TEM) and in situ reflection high energy-electron diffraction (RHEED), we find that MgO texturing is a nucleation-controlled process and the alignment is a function of nuclei size and density. This differs greatly from the evolutionary-type texturing process observed for IBAD (100) YSZ. Consequently, we are able to make 100 Å thick MgO films with 7° in-plane alignment, whereas IBAD (100) YSZ films need to be thicker than 5000 Å to achieve in-plane alignment better than 13°. This has important implications for the economical application of IBAD induced alignment in real manufacturing processes, including high Tc superconductor (i.e., YBCO) coated tapes, photovoltaics, magnetic thin films, and semiconductor devices. © 1997 American Institute of Physics.
Show PACS
81.15.Jj Ion and electron beam-assisted deposition; ion plating
68.55.-a Thin film structure and morphology
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

A novel dual-gate high electron mobility transistor using a split-gate structure

N. J. Collier and J. R. A. Cleaver

Appl. Phys. Lett. 71, 2958 (1997); http://dx.doi.org/10.1063/1.120228 (3 pages)

Full Text: | Download PDF

Show Abstract
The split-gate concept has been applied to dual-gate high electron mobility structures for room-temperature operation. The gates are configured so that the second gate is in close proximity to the gap defined by the split-gate electrodes. This allows both gates to control the carrier density in the same region of the device, so that it is possible to control the threshold voltage for either gate by altering the bias at which the other gate is held. The effect of changing the gate configuration is demonstrated. © 1997 American Institute of Physics.
Show PACS
85.30.Tv Field effect devices
73.61.Ey III-V semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance

Surface step bunching and crystal defects in InAlAs films grown by molecular beam epitaxy on (111)B InP substrates

N. Bécourt, F. Peiró, A. Cornet, J. R. Morante, P. Gorostiza, G. Halkias, K. Michelakis, and A. Georgakilas

Appl. Phys. Lett. 71, 2961 (1997); http://dx.doi.org/10.1063/1.120229 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
The surface morphology and crystal structure of InAlAs films grown by molecular beam epitaxy on (111)B InP substrates misoriented 1° toward [211] have been investigated. Combined plane view transmission electron microscopy and atomic force microscopy observations have revealed spectacular terracelike topographies, induced by surface step bunching during the growth. Furthermore, cross section transmission electron microscopy analysis has shown the presence of threading dislocations, related to the giant steps, as well as strain inhomogeneities attributed to composition modulation. We have also demonstrated the potential use of the giant steps for local deposition of InAs. © 1997 American Institute of Physics.
Show PACS
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Low temperature photo-oxidation of silicon using a xenon excimer lamp

Jun-Ying Zhang and Ian W. Boyd

Appl. Phys. Lett. 71, 2964 (1997); http://dx.doi.org/10.1063/1.120230 (3 pages) | Cited 25 times

Full Text: | Download PDF

Show Abstract
Low temperature (250 °C) photo-oxidation of silicon initiated by a Xe2∗ excimer lamp operating at a wavelength of 172 nm has been investigated. The induced reaction rate of 0.1 nm/min is 90 times greater than thermal oxidation at 612 °C and more than three times greater than that previously obtained at 350 °C using a low pressure mercury lamp. It was found to be strongly dependent upon oxygen pressure with the highest rates being achievable below 10 mbar. Ellipsometry, Fourier transform infrared spectroscopy, capacitance–voltage, and current–voltage measurements have been employed to characterize the oxide films and designate them as high quality. © 1997 American Institute of Physics.
Show PACS
81.05.Cy Elemental semiconductors
81.65.Mq Oxidation
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
78.66.Nk Insulators
78.30.Hv Other nonmetallic inorganics

Transverse energy spread of photoelectrons emitted from GaAs photocathodes with negative electron affinity

S. Pastuszka, D. Kratzmann, D. Schwalm, A. Wolf, and A. S. Terekhov

Appl. Phys. Lett. 71, 2967 (1997); http://dx.doi.org/10.1063/1.120231 (3 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
The mean transverse energy (MTE) of electrons emitted from GaAs photocathodes was measured systematically using a new method based on adiabatic transverse expansion of an electron beam in a spatially decreasing magnetic field. Electrons with energies above the conduction band minimum are found to be thermalized with the lattice temperature of the cathode while electrons having suffered energy losses prior to their emission show enhanced transverse energies. For (Cs,O) and (Cs,F) activation layers on the same cathode the same MTE is found. By cooling the cathode with liquid nitrogen, the MTE of the high-energy electrons was reduced to ≈ 14 meV. © 1997 American Institute of Physics.
Show PACS
85.60.Ha Photomultipliers; phototubes and photocathodes
79.60.Bm Clean metal, semiconductor, and insulator surfaces
71.20.Nr Semiconductor compounds

Atomic origin of deep levels in p-type GaN: Theory

D. J. Chadi

Appl. Phys. Lett. 71, 2970 (1997); http://dx.doi.org/10.1063/1.120232 (2 pages) | Cited 18 times

Full Text: | Download PDF

Show Abstract
Experimentally identified deep levels in p-type GaN at approximately 0.9–1, 1.4, and 1.8–2 eV above the valence-band maximum have been attributed to Ga vacancies. From the results of first-principles calculations, we find that from both energetic and electronic level structure standpoints it is necessary to consider the structural modification VGa→Nanti+VN, resulting from the transfer of a nearest-neighbor N atom to a Ga-vacancy site (VGa) to explain the levels at 1 and 2 eV. Isolated N-antisite (Nanti) and nitrogen-vacancy (VN) defects are found to give rise to additional deep levels at 1.4 and 0.8 eV, respectively. © 1997 American Institute of Physics.
Show PACS
71.55.Eq III-V semiconductors
61.72.J- Point defects and defect clusters
71.15.Dx Computational methodology (Brillouin zone sampling, iterative diagonalization, pseudopotential construction)

Structural and optical properties of vertically aligned InP quantum dots

M. K. Zundel, P. Specht, K. Eberl, N. Y. Jin-Phillipp, and F. Phillipp

Appl. Phys. Lett. 71, 2972 (1997); http://dx.doi.org/10.1063/1.120233 (3 pages) | Cited 75 times

Full Text: | Download PDF

Show Abstract
Stacked layers of self-assembled InP quantum dots embedded in Ga0.52In0.48P have been prepared by solid source molecular beam epitaxy. Thereby the distance between the dot layers has been varied from 2 to 16 nm. Cross sectional transmission electron microscopy shows that the InP dots are aligned in the growth direction [100]. As the distance between the dot layers is reduced, each dot of the first dot layer is reproduced in the upper layers, and this leads to an improvement of the dot size homogeneity of the stacked InP dot system. This is confirmed by photoluminescence (PL) measurements, which demonstrate a very narrow linewidth of 26 meV for a triple layer with 2 nm separation between the dot layers in comparison with a linewidth of 41 meV for a single layer sample. At the same time, the PL peak of the dots is shifted by 72 meV to lower energies which is ascribed to a reduced strain and strong electrical coupling between the densely stacked InP dots. © 1997 American Institute of Physics.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.55.Cr III-V semiconductors

Direct excitation spectroscopy of Er centers in porous silicon

M. Stepikhova, W. Jantsch, G. Kocher, L. Palmetshofer, M. Schoisswohl, and H. J. von Bardeleben

Appl. Phys. Lett. 71, 2975 (1997); http://dx.doi.org/10.1063/1.120234 (3 pages) | Cited 21 times

Full Text: | Download PDF

Show Abstract
We report direct excitation of optically active Er centers in porous Si. Excitation spectroscopy performed close to the intracenter 4I15/2→4I11/2 and 4I15/2→4I9/2 transitions of Er3+ (4f11) ions allows us to identify two kinds of Er centers in porous Si: (i) Er diffused into porous nanograins with lower than cubic symmetry and (ii) Er centers incorporated in an amorphous silicalike matrix. The latter show much weaker thermal quenching of the Er3+ emission which decreases only by a factor of eight when the temperature is increased from 4.2 K up to 360 K. © 1997 American Institute of Physics.
Show PACS
78.55.Mb Porous materials
71.55.Cn Elemental semiconductors

Ultrathin SiOxNy by rapid thermal heating of silicon in N2 at T = 760–1050 °C

M. L. Green, T. Sorsch, L. C. Feldman, W. N. Lennard, E. P. Gusev, E. Garfunkel, H. C. Lu, and T. Gustafsson

Appl. Phys. Lett. 71, 2978 (1997); http://dx.doi.org/10.1063/1.120235 (3 pages) | Cited 12 times

Full Text: | Download PDF

Show Abstract
In this letter, we report on the reaction between Si and N2 in the temperature range of 760–1050 °C, in a rapid thermal processing chamber. Gas phase impurities such as H2O, O2, and H2, which can outgas from the cold walls of the chamber, mediate the Si/N2 reaction, resulting in the formation of SiOxNy. The oxynitridation can be explained by equilibrium chemical thermodynamics, in contrast to the case of oxynitridation using N2O or NO, where the nitrogen is incorporated under nonequilibrium conditions. Using nuclear reaction analysis, we have measured nitrogen contents as high as 2.5×1015 N/cm2 (the equivalent of more than 3 monolayers) in these new dielectrics. They can be reoxidized to form ultrathin (2 to 3 nm) dielectrics. © 1997 American Institute of Physics.
Show PACS
81.05.Cy Elemental semiconductors
81.65.Mq Oxidation
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
81.65.Lp Surface hardening: nitridation, carburization, carbonitridation

Investigations of Stranski-Krastanov growth kinetics of Si-dots on 6H-SiC(0001)

Andreas Fissel, Kay Pfennighaus, and Wolfgang Richter

Appl. Phys. Lett. 71, 2981 (1997); http://dx.doi.org/10.1063/1.120236 (3 pages) | Cited 10 times

Full Text: | Download PDF

Show Abstract
The growth kinetics of Si dots grown on 6H-SiC(0001) by molecular beam epitaxy were studied in real time by reflection high-energy electron diffraction. The critical thickness for the Stranski–Krastanov growth mode transition was found to be kinetically delayed leading to a gradual decrease of this thickness with increasing temperature (T). At T<625 °C and coverages below the critical thickness, a post-deposition evolution of dots is clearly established. The dot growth process is, under these conditions, mainly determined by the mass transfer out of the two-dimensional layer towards the Si dots. The dots grown on top of a 1 monolayer (ML) thick wetting layer are quantum sized with typical dimensions of 5–6 nm in height and 20–30 nm in diameter after a long post-deposition evolution times at 2–3 ML coverages. Above 625 °C and coverages above the critical thickness, the dot growth is only determined by surface-diffusion kinetics resulting in the growth of larger dots. © 1997 American Institute of Physics.
Show PACS
81.05.Cy Elemental semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.35.Fx Diffusion; interface formation

Growth of HgCdTe and CdTe(331)B on germanium substrate by molecular beam epitaxy

J. P. Zanatta, P. Duvaut, P. Ferret, A. Million, G. Destefanis, P. Rambaud, and C. Vannuffel

Appl. Phys. Lett. 71, 2984 (1997); http://dx.doi.org/10.1063/1.120237 (3 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
The choice of germanium as a substrate for CdTe and HgCdTe (MCT) epitaxial films is discussed. Ge appears to be a good candidate to solve the weakness of CdTe homosubstrates. Direct growth of CdTe(331) B 4° off epitaxial films was achieved on a Ge (001) substrate tilted 8° around [110] by molecular beam epitaxy (MBE). Hence MCT(331) 4° off MBE epilayers were grown and characterized. The surface morphology was smooth and mirrorlike. X-ray double-crystal rocking curve on (331) planes showed full-width at half-maximum of 130 arc sec. Transmission electron microscopy is also reported to show the misfit accommodation at the CdTe/Ge interface; two domains were observed close to the interface but only a (331) orientation remained after a 50-nm-thick growth. The first photodiodes on MCT on Ge were fabricated and exhibited high performances: for a cutoff wavelength value of 5.24 μm at T = 77 K, the shunt impedance measured was 6.6×109 Ω and the R0A product was 1.8×105 Ω cm2. © 1997 American Institute of Physics.
Show PACS
81.05.Dz II-VI semiconductors
68.55.-a Thin film structure and morphology
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.35.Ct Interface structure and roughness
85.60.Dw Photodiodes; phototransistors; photoresistors

Resistless patterning for selective growth

Kumar Shiralagi, Raymond Tsui, and Herbert Goronkin

Appl. Phys. Lett. 71, 2987 (1997); http://dx.doi.org/10.1063/1.120238 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
We present a simple and novel method of resistlessly patterning GaAs substrates with an oxide mask. The GaAs surface native oxide is optically modified into a stable gallium oxide mask, which then allows InAs to be grown with excellent selectivity by chemical beam epitaxy. The conventional approach to pattern wafers for selective growth is to use photoresist to pattern the silicon nitride or oxide first deposited on the wafers. Photoresist residue can remain even after elaborate cleaning and the molecular scale features can impede selectivity during growth. This method is a one-step resistless process that eliminates such photoresist related problems. Our understanding of the patterning process and results on the selective growth of InAs are presented. © 1997 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
81.65.Cf Surface cleaning, etching, patterning
85.40.Hp Lithography, masks and pattern transfer
81.65.Mq Oxidation
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
82.50.-m Photochemistry

Potential controlled stripping of an amorphous As layer on GaAs(001) in an electrolyte: An in situ x-ray scattering study

G. Scherb, A. Kazimirov, J. Zegenhagen, T. Schultz, R. Feidenhans’l, and B. O. Fimland

Appl. Phys. Lett. 71, 2990 (1997); http://dx.doi.org/10.1063/1.120239 (3 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
We demonstrate that an amorphous As layer deposited as protection on a GaAs(001) surface grown by molecular beam epitaxy can be removed via reductive etching in an electrolytical cell at sufficiently negative electrode potentials. Employing a specially constructed electrochemical cell filled with H2SO4, we monitored the stripping process of the 50 nm As cap over a period of hours in situ with x-ray diffraction. Our results suggest that, using this potential controlled stripping, smooth and well ordered GaAs(001) surfaces can be obtained in an aqueous electrolyte. © 1997 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
82.45.-h Electrochemistry and electrophoresis
81.65.-b Surface treatments

The V3+ center in AlN

P. Thurian, I. Loa, P. Maxim, A. Hoffmann, C. Thomsen, and K. Pressel

Appl. Phys. Lett. 71, 2993 (1997); http://dx.doi.org/10.1063/1.120240 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
We investigated the magnetooptical properties of 0.9 eV luminescence in AlN. The zero-phonon lines at 0.943 eV in AlN are attributed to a transition within a d2 configuration because of a characteristic threefold ground-state splitting in magnetic fields. We determine a g value of 1.96±0.07 and a zero-field splitting of 120±30 μeV for the 3A2(F) ground state. On the basis of the temperature dependence in a magnetic field, we attribute the 0.943 eV zero-phonon line in AlN to the 1E(D)–3A2(F) transition of isolated V3+. The different fine structures of the excited state in AlN and GaN are explained in a Tanabe–Sugano diagram. © 1997 American Institute of Physics.
Show PACS
71.55.Eq III-V semiconductors
78.20.Ls Magneto-optical effects
63.20.-e Phonons in crystal lattices
78.55.Cr III-V semiconductors
71.70.Ch Crystal and ligand fields

Planar aluminum-implanted 1400 V 4H silicon carbide p-n diodes with low on resistance

D. Peters, R. Schörner, K.-H. Hölzlein, and P. Friedrichs

Appl. Phys. Lett. 71, 2996 (1997); http://dx.doi.org/10.1063/1.120241 (2 pages) | Cited 21 times

Full Text: | Download PDF

Show Abstract
Planar p-n diodes with edge termination were fabricated by aluminum implantation on n-type 4H silicon carbide. These diodes exhibited an excellent blocking behavior up to 1400 V reverse voltage with stable avalanche breakdown at an electric field strength of 2.8 MV/cm. In addition, a nearly classical forward characteristic was observed with both recombination and diffusion current mechanism represented by ideality factors of 1.05 and 1.93, respectively. The turn-on voltage was 2.8 V. At a forward voltage drop of 6.2 V a current density of 4000 A/cm2 and a differential on resistance below 1 mΩ cm2 were achieved. © 1997 American Institute of Physics.
Show PACS
85.30.Kk Junction diodes
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
61.72.up Other materials
73.61.Le Other inorganic semiconductors
61.80.Jh Ion radiation effects
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
85.40.Ry Impurity doping, diffusion and ion implantation technology
77.22.Jp Dielectric breakdown and space-charge effects

The kinetics of intermixing of GaAs/AlGaAs quantum confined heterostructures

A. Saher Helmy, J. S. Aitchison, and J. H. Marsh

Appl. Phys. Lett. 71, 2998 (1997); http://dx.doi.org/10.1063/1.120242 (3 pages) | Cited 15 times

Full Text: | Download PDF

Show Abstract
An atomic-scale model for the kinetics of intermixing of GaAs/AlGaAs, quantum confined heterostructures is presented. It quantifies the effects of the statistical nature of defect diffusion through heterostructures on the Ga/Al interdiffusion across such an interface. The model has been validated by successfully predicting the observed amounts of quantum well intermixing induced by a hydrogen plasma induced defect layer intermixing process. Agreement within 30% of the measurements was obtained for values of the surface release velocity>1 μm s1. © 1997 American Institute of Physics.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
66.30.Ny Chemical interdiffusion; diffusion barriers
68.35.Fx Diffusion; interface formation

Photothermal reflectance investigation of ion implanted 6H–SiC

K. L. Muratikov, I. O. Usov, H. G. Walther, H. Karge, and A. V. Suvorov

Appl. Phys. Lett. 71, 3001 (1997); http://dx.doi.org/10.1063/1.120243 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The photoreflection method is applied to detailed characterization of the ion implanted silicon carbide. Experimentally and theoretically, it is shown that the photoreflection method can be an effective tool for the determination of the dose of implantation and the depth of the implanted layer. It is demonstrated that the photoreflection method also has a high sensitivity to the measurement of optical parameters of the implanted layer. Experimental results are presented for the case of Lely grown 6H–SiC crystals implanted by 37 keV He+ ions. © 1997 American Institute of Physics.
Show PACS
78.20.-e Optical properties of bulk materials and thin films
65.90.+i Other topics in thermal properties of condensed matter (restricted to new topics in section 65)
78.20.N- Thermo-optic effects
78.20.nb Photothermal effects
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
61.72.up Other materials
61.80.Jh Ion radiation effects
85.40.Ry Impurity doping, diffusion and ion implantation technology

Post growth rapid thermal annealing of GaN: The relationship between annealing temperature, GaN crystal quality, and contact-GaN interfacial structure

M. W. Cole, F. Ren, and S. J. Pearton

Appl. Phys. Lett. 71, 3004 (1997); http://dx.doi.org/10.1063/1.120244 (3 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
Microstructure of GaN films grown by metalorganic chemical-vapor-deposition (MOCVD) on c-sapphire substrates has been accessed as a function of post-growth rapid thermal annealing (RTA) temperatures from 600 °C to 800 °C. The influence of the thermally modified, near-surface crystalline quality on sputtered WSi contact to GaN was also evaluated. Similar planar defects were observed in all heat treated samples; only their density differed. Our analyses demonstrated a strong relationship between the improved GaN crystal quality and postgrowth high-temperature thermal processing. The density of the near-surface defects was lowered by 61% as the annealing temperature was raised from 600 °C to 800 °C. Depression of the near-surface defects encouraged development of the β-W2N interfacial phase and promoted metal-semiconductor interface smoothness. © 1997 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Cc Kinetics of defect formation and annealing
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.35.B- Structure of clean surfaces (and surface reconstruction)

Substrate imposed stress-strain effect on photoluminescence in hydrogenated amorphous silicon alloys

Keunjoo Kim, M. S. Suh, H. W. Shim, C. J. Youn, E-K. Suh, K. B. Lee, H. J. Lee, Hwack Joo Lee, and Hyun Ryu

Appl. Phys. Lett. 71, 3007 (1997); http://dx.doi.org/10.1063/1.120245 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Hydrogenated amorphous silicon films were deposited on the unstrained and strained Si substrates by an electron cyclotron resonance plasma source. The photoluminescence spectra show that emission energies are different from each other. The redshift of photoluminescence induced by the biaxial tensile stress is increased with decreasing the temperature in the range of 0.11–0.17 eV. The stress effect also enhances the quantum efficiency significantly. The pseudomorphic growth of Si on a relaxed Si0.75Ge0.25 (100) surface provides the strain energy of about 0.17 eV. These comparable results indicate that the shift of emission energy is attributed to the stress effect perturbing the polysilane structure. © 1997 American Institute of Physics.
Show PACS
78.66.Db Elemental semiconductors and insulators
78.66.Jg Amorphous semiconductors; glasses
78.55.Ap Elemental semiconductors
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects
68.55.-a Thin film structure and morphology
68.60.Bs Mechanical and acoustical properties
81.05.Gc Amorphous semiconductors
81.05.Cy Elemental semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.43.Dq Amorphous semiconductors, metals, and alloys

Critical-current measurements in planar Josephson junctions

M. S. Rzchowski and B. M. Hinaus

Appl. Phys. Lett. 71, 3010 (1997); http://dx.doi.org/10.1063/1.120246 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The properties of planar high-temperature superconducting Josephson junctions are not entirely consistent with low Tc models. Some of these disparities may be intrinsic, related to the unusual superconducting properties of the electrodes, while others are due to the nonstandard planar geometry. By comparing experimental measurements of a 24° bicrystal substrate Josephson junction with a simple model of nonuniform current flow in a planar geometry, we show that several unusual properties can be explained as extrinsic. We show that nonuniform current feed in a planar geometry leads to a reduced critical current, an unchanged Meissner field Hco, and a power-law dependence of the critical current on Hco different from that expected in an overlap geometry. © 1997 American Institute of Physics.
Show PACS
74.50.+r Tunneling phenomena; Josephson effects
74.72.-h Cuprate superconductors
74.25.Sv Critical currents
74.25.Ha Magnetic properties including vortex structures and related phenomena
85.25.Cp Josephson devices

Solution deposition and heteroepitaxial crystallization of LaNiO3 electrodes for integrated ferroelectric devices

Chae Ryong Cho, David A. Payne, and Seong Lae Cho

Appl. Phys. Lett. 71, 3013 (1997); http://dx.doi.org/10.1063/1.120247 (3 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
Electrically conducting LaNiO3 (LNO) thin layers were deposited on (100)SrTiO3 (STO) and (100)LaAlO3 (LAO) substrates and crystallized at temperatures between 700 and 800 °C. The chemical method of deposition was solution sol-gel processing. X-ray 2θ and rocking curve measurements, ϕ scans, and atomic force microscopy studies revealed the degree of crystallinity and heteroepitaxy for the integrated electrodes. The full-width at half-maximum for (100) LNO deposited on LAO and STO was 0.16° and 0.25°, respectively. Surface bonding states and chemistry were examined by x-ray photoelectron spectroscopy. The room temperature resistivity of LNO electrodes deposited on STO and LAO was 460 and 340 μΩ cm, respectively. © 1997 American Institute of Physics.
Show PACS
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
68.35.B- Structure of clean surfaces (and surface reconstruction)
73.20.At Surface states, band structure, electron density of states
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
72.20.Fr Low-field transport and mobility; piezoresistance
72.15.Nj Collective modes (e.g., in one-dimensional conductors)

Transparent nanocrystalline diamond ceramics fabricated from C60 fullerene by shock compression

H. Hirai, K. Kondo, M. Kim, H. Koinuma, K. Kurashima, and Y. Bando

Appl. Phys. Lett. 71, 3016 (1997); http://dx.doi.org/10.1063/1.120248 (3 pages) | Cited 13 times

Full Text: | Download PDF

Show Abstract
Transparent nanocrystalline diamond ceramics, consisting of a few nanometer-sized diamond crystallites that are unstable in themselves because of higher surface energy, were fabricated successfully from C60 fullerene using a shock compression and rapid quenching technique. The platelets were transparent and very hard, nearly comparable to type IIa diamond. Transmission electron microscopy and electron energy loss spectroscopy revealed that individual crystallites had combined directly or through a very thin and modified sp3 carbon layer, which possibly stabilized the nanometer-sized crystallites. The size order and sp3 configuration of the nanotexture caused the transparency and hardness of the present material. © 1997 American Institute of Physics.
Show PACS
81.05.ub Fullerenes and related materials
61.46.-w Structure of nanoscale materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
68.35.Md Surface thermodynamics, surface energies
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
81.30.Fb Solidification
79.20.Kz Other electron-impact emission phenomena
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
62.20.Qp Friction, tribology, and hardness
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.50.-p High-pressure effects in solids and liquids
Page 2 of 2 Pages Previous Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close