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

23 Feb 2009

Volume 94, Issue 8, Articles (08xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 94, 082501 (2009); http://dx.doi.org/10.1063/1.3085971 (3 pages)

Chunghee Nam, B. G. Ng, F. J. Castaño, M. D. Mascaro, and C. A. Ross
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Electromigration-induced bond improvement for three-dimensional integrated circuits

H. L. Leong, C. L. Gan, C. V. Thompson, K. L. Pey, and H. Y. Li

Appl. Phys. Lett. 94, 081901 (2009); http://dx.doi.org/10.1063/1.3081456 (3 pages) | Cited 2 times

Online Publication Date: 24 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Bonded Cu interconnects were stressed with increasing current while the contact resistance was measured. Interconnects with high initial contact resistance exhibited a contact resistance reduction phenomenon at a critical current density. The higher the initial contact resistance is, the lower the current required to trigger this phenomenon. Interconnects with low initial contact resistances exhibit this phenomenon only when stressed at a higher temperature. Electromigration is shown to be the most likely mechanism responsible for this phenomenon. This behavior can be used for low-temperature improvement of the quality of bonded interconnects for three-dimensional integrated circuits.
Show PACS
85.40.Ls Metallization, contacts, interconnects; device isolation
66.30.Qa Electromigration
73.40.Cg Contact resistance, contact potential

Effect of the electrical boundary condition at the crack face on the mode I energy release rate in piezoelectric ceramics

Yasuhide Shindo, Fumio Narita, and Mitsuru Hirama

Appl. Phys. Lett. 94, 081902 (2009); http://dx.doi.org/10.1063/1.3088855 (3 pages) | Cited 7 times

Online Publication Date: 24 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper discusses the crack behavior of rectangular piezoelectric ceramics under electromechanical loading. A finite element analysis was employed to calculate the fracture mechanics parameters such as mode I energy release rate for the permeable, impermeable, and open crack models. Recently proposed nonlinear electrically discharging crack model was also considered. The effect of applied electric fields on the fracture mechanics parameters was then examined under various electrical boundary conditions at the crack face.
Show PACS
77.65.-j Piezoelectricity and electromechanical effects
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.mt Cracks
62.20.mm Fracture
02.70.Dh Finite-element and Galerkin methods
77.84.-s Dielectric, piezoelectric, ferroelectric, and antiferroelectric materials

The intrinsic elasticity of twin walls: Ferrielectric twin walls in ferroelastic CaTiO3

Liliana Goncalves-Ferreira, Simon A. T. Redfern, Emilio Atacho, and Ekhard K. H. Salje

Appl. Phys. Lett. 94, 081903 (2009); http://dx.doi.org/10.1063/1.3089690 (3 pages) | Cited 8 times

Online Publication Date: 24 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Computer simulation of ferrielectric domain walls in ferroelastic CaTiO3 demonstrate that twin walls possess almost the same compressibility as the bulk. The Ti–Ti repetition length inside the wall is approximately 0.2% greater than the equivalent lattice parameter of the bulk. A slight reduction in the uniaxial compressibility perpendicular to the twin wall is compared with predictions of various theoretical models which give either large softening or large hardening. Simple spring models predict correctly that any change is expected to be small for relevant potentials far from the ferroelastic transition point.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.60.Ch Domain walls and domain structure
75.50.Gg Ferrimagnetics
75.80.+q Magnetomechanical effects, magnetostriction
75.40.Cx Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.)

Effect of oxygen vacancies on the red emission of SrTiO3:Pr3+ phosphor films

Wei Wang, Chunge Jiang, Mingrong Shen, Liang Fang, Fengang Zheng, Xinglong Wu, and Jiancang Shen

Appl. Phys. Lett. 94, 081904 (2009); http://dx.doi.org/10.1063/1.3089814 (3 pages) | Cited 7 times

Online Publication Date: 25 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The red emission of the Pr3+ ions was very sensitive to the oxygen vacancies in the host of 300-nm-thick SrTiO3 films. Comparing with the air-annealed films, a significant enhancement of up to 400% was observed in the red photoluminescence intensity for the vacuum-annealed samples, and the valence state of the Pr ions was found to be changed little. Based on the fact of the obvious overlap between the excitation band of the Pr3+ ions and emission band of the oxygen vacancies, it was suggested that the oxygen vacancies act as a sensitizer for the effective energy transfer from SrTiO3 host to Pr3+ ions. This study demonstrated that the red emission from Pr3+ ions in SrTiO3 was closely related to the oxygen vacancies.
Show PACS
61.72.jd Vacancies
68.55.aj Insulators
78.66.Nk Insulators
78.55.Hx Other solid inorganic materials

Tuning of Fermi level position at HfNx/SiO2 interface

J. A. Rothschild and M. Eizenberg

Appl. Phys. Lett. 94, 081905 (2009); http://dx.doi.org/10.1063/1.3089818 (3 pages) | Cited 3 times

Online Publication Date: 25 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate that the vacuum work function of HfNx, as measured in situ by Kelvin probe, can be tailored on the entire silicon band gap by changing the nitrogen content of the HfNx alloy. We observed an increase in the effective work function of HfNx on SiO2, extracted from capacitance-voltage measurements, only for x<1, and saturation is reached at a value of 4.6 eV for x>1. The measured value of the effective work function for pure Hf (4.1 eV) can be explained by the metal induced gap states model, while the HfNx behavior is explained by oxidation at the HfNx/SiO2 interface.
Show PACS
73.20.At Surface states, band structure, electron density of states
73.30.+y Surface double layers, Schottky barriers, and work functions

Surface morphology and electronic structure of bulk single crystal β-Ga2O3(100)

T. C. Lovejoy, E. N. Yitamben, N. Shamir, J. Morales, E. G. Villora, K. Shimamura, S. Zheng, F. S. Ohuchi, and M. A. Olmstead

Appl. Phys. Lett. 94, 081906 (2009); http://dx.doi.org/10.1063/1.3086392 (3 pages) | Cited 12 times

Online Publication Date: 26 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Experimental studies of the surface morphology and electronic structure of bulk single crystals of the transparent and wide gap semiconductor gallium oxide (β-Ga2O3) have been conducted using scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and angle-resolved photoemission spectroscopy (ARPES). Atomically resolved STM and LEED results for the β-Ga2O3(100) surface clarify that the predominant surface termination contains both gallium and oxygen, and this surface does not exhibit a reconstruction. The valence band structure was obtained with ARPES and shows good agreement with existing theoretical works at the zone center and along the a∗ and c∗ directions, except that the calculated bandwidth is ∼ 7% too small. There is poorer agreement along the b∗ direction, where the experimental bands disperse more strongly than the calculations.
Show PACS
68.35.bg Semiconductors
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.47.Fg Semiconductor surfaces
71.20.Nr Semiconductor compounds
79.60.Bm Clean metal, semiconductor, and insulator surfaces

Negative permittivity and permeability of gold square nanospirals

R. Abdeddaïm, G. Guida, A. Priou, B. Gallas, and J. Rivory

Appl. Phys. Lett. 94, 081907 (2009); http://dx.doi.org/10.1063/1.3086873 (3 pages) | Cited 8 times

Online Publication Date: 26 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The optical properties of square nanospirals made of gold have been investigated numerically in the hundred terahertz range as a function of the geometrical parameters of the nanospirals. It is shown that the permittivity values of the nanospirals originate from the longitudinal surface plasmon resonances of the arms composing the nanospirals. A magnetic resonance was also observed whose magnitude and position increased with the number of winding. Above three windings the gold nanospirals exhibited negative values of the real part of the permeability above 400 THz.
Show PACS
78.66.Bz Metals and metallic alloys
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
77.22.Ch Permittivity (dielectric function)

Mechanism of particle removal by megasonic waves

Wonjung Kim, Tae-Hong Kim, Jaehyuck Choi, and Ho-Young Kim

Appl. Phys. Lett. 94, 081908 (2009); http://dx.doi.org/10.1063/1.3089820 (3 pages) | Cited 12 times

Online Publication Date: 26 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We elucidate the major mechanism of microparticle removal in the megasonic cleaning process through the direct visualization experiments. It is revealed that particles sitting on solids are removed by adjacent microbubbles that oscillate near the substrates and exert interfacial and pressure gradient forces on the particles. Other pressure and streaming effects are shown to be too weak to detach the particles.
Show PACS
43.35.Zc Use of ultrasonics in nondestructive testing, industrial processes, and industrial products
68.35.Iv Acoustical properties
68.35.Ja Surface and interface dynamics and vibrations

Proton-exchanged OH− absorption spectra of highly Zn-doped LiNbO3 with and without polarization inversion

Pei-Chang Tsai, Chih-Ta Chia, Shou-Tai Lin, Yen-Chieh Huang, Hsiu-Feng Lu, and Sheng-Hsien Lin

Appl. Phys. Lett. 94, 081909 (2009); http://dx.doi.org/10.1063/1.3089836 (3 pages) | Cited 1 time

Online Publication Date: 26 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The proton-exchanged OH− absorption spectra of congruent and 8.1 mol % Zn-doped LiNbO3 single crystals with and without polarization inversion are presented. The variation in the proton-exchanged OH− spectra for the congruent sample is not affected by polarization inversion. This result confirms the Li-vacancy model. However, the highly doped sample shows stronger increase in intensities with polarization inversion. In our investigation, highly negative charge vacancy model confirms with proton-exchanged OH− absorption spectra and domain inversion etching experiment. Finally, we demonstrated the polarization inversion mechanism with these two samples based on extended x-ray-absorption fine structure experimental results.
Show PACS
78.70.Dm X-ray absorption spectra
81.10.Fq Growth from melts; zone melting and refining
61.72.jd Vacancies
61.72.up Other materials
61.66.Fn Inorganic compounds

Structural analyses of strained SiGe wires formed by hydrogen thermal etching and Ge-condensation processes

Tsutomu Tezuka, Eiji Toyoda, Toshifumi Irisawa, Norio Hirashita, Yoshihiko Moriyama, Naoharu Sugiyama, Koji Usuda, and Shin-ichi Takagi

Appl. Phys. Lett. 94, 081910 (2009); http://dx.doi.org/10.1063/1.3086884 (3 pages) | Cited 1 time

Online Publication Date: 27 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Strained SiGe-wire structures formed by a thermal oxidation of SiGe-on-insulator (SGOI) fins after an anisotropic gas etching in atmospheric hydrogen are investigated in terms of morphology, strain, and crystalline defects. It is found that vertical and smooth {110} sidewalls emerged on the SGOI fins after the hydrogen etching and that the SiGe wires consisted of a Si-rich core region and a surrounding Ge-rich layer formed by the Ge-condensation mechanism through the oxidation. Detailed strain analyses reveal that uniaxial and compressive strain accumulated in the Ge-rich layer via an elastic lattice deformation without generating dislocations.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
85.30.Tv Field effect devices
81.65.Cf Surface cleaning, etching, patterning
81.65.Mq Oxidation
81.40.Lm Deformation, plasticity, and creep
81.40.Jj Elasticity and anelasticity, stress-strain relations

Optical properties of GaSb/GaAs type-ІІ quantum dots grown by droplet epitaxy

Takuya Kawazu, Takaaki Mano, Takeshi Noda, and Hiroyuki Sakaki

Appl. Phys. Lett. 94, 081911 (2009); http://dx.doi.org/10.1063/1.3090033 (3 pages) | Cited 12 times

Online Publication Date: 27 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study the optical properties of GaSb/GaAs type-ІІ quantum dots (QDs) on a GaAs substrate grown by droplet epitaxy. Ga droplets are formed on GaAs and then exposed to Sb flux to be clad by large granular crystals of Sb. Then the sample was annealed at 380 °C to enhance the reaction of Ga droplets with Sb and to evaporate the excess granular layer. In photoluminescence (PL) measurements, the peaks of the QDs and wetting layer (WL) are observed. The PL intensity of the QDs is much stronger than that of the WL, where the ratio IQD/IWL of the integral intensities is about 13.3. The PL peaks shift toward higher energies with increasing excitation energy, suggesting that the band lineups exhibit a type-ІІ staggered alignment. In addition, we investigate the temperature dependences of the PL peak energy and intensity.
Show PACS
78.67.Hc Quantum dots
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
68.08.Bc Wetting
68.65.Hb Quantum dots (patterned in quantum wells)
78.55.Cr III-V semiconductors

Thermal conductivity and interface thermal conductance of amorphous and crystalline Zr47Cu31Al13Ni9 alloys with a Y2O3 coating

Nitin C. Shukla, Hao-Hsiang Liao, Jeremiah T. Abiade, Fengxiao Liu, Peter K. Liaw, and Scott T. Huxtable

Appl. Phys. Lett. 94, 081912 (2009); http://dx.doi.org/10.1063/1.3090487 (3 pages) | Cited 4 times

Online Publication Date: 27 February 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We examine the thermal conductivity k and interface thermal conductance G for amorphous and crystalline Zr47Cu31Al13Ni9 alloys in contact with polycrystalline Y2O3. Using time-domain thermoreflectance, we find k = 4.5 W m−1 K−1 for the amorphous metallic alloy of Zr47Cu31Al13Ni9 and k = 5.0 W m−1 K−1 for the crystalline Zr47Cu31Al13Ni9. We also measure G = 23 MW m−2 K−1 for the metallic glass/Y2O3 interface and G = 26 MW m−2 K−1 for the interface between the crystalline Zr47Cu31Al13Ni9 and Y2O3. The thermal conductivity of the crystalline Y2O3 layer is found to be k = 5.0 W m−1 K−1, and the conductances of Al/Y2O3 and Y2O3/Si interfaces are 68 and 45 MW m−2 K−1, respectively.
Show PACS
73.40.Ns Metal-nonmetal contacts
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close