摘要:

Ferroelectric lead lanthanum titanate (PLT) thin films with various lanthanum concentration were fabricated by sol-gel spin-on process ontoPt/Ti/SiO2/Sisubstrates. We investigated the crystal structure, microstructure, and dielectric and ferroelectric properties of PLT films according to lanthanum doping concentration. The films annealed at600 °Cfor 30 min have the single perovskite phase having only tetragonal or pseudocubic structure. The film microstructures were changed according to the doping concentration of La. The PLT films showed the typical polarization-electric field hysteresis loops and capacitance-voltage characteristics representing the ferroelectric switching property. The coercive field and remanent polarization decreased due to the phase transformation from ferroelectric to paraelectric phase with increasing La concentration. The effective dielectric constant and the leakage current density increased according to the increase of La content. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120717

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The electrical properties of chromium-related defects in GaP are investigated. Using deep-level transient spectroscopy, a related deep level is observed inp-type GaP exhibiting an activation energy, associated with hole emission, of 0.5 eV. Detailed capacitance transient investigations were undertaken to study the electric field dependence. This emission rate which is found to have a field dependence can be fitted by a Poole–Frenkel model. Evidence is given that the trap is theCr4+/3+deep donor level in GaP caused by substitutional Cr on Ga sites. This trap seems to be well adapted to compensate donors for the growth of the semi-insulating GaP. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120718

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We have investigated the deposition of size-selected metal clusters(Ag400)onto a stepped graphite surface. The clusters were produced with an inert gas condensation cluster source and were imaged on the surface with a high-resolution scanning electron microscope. For modest cluster deposition energies, cluster aggregation is much more limited at the steps than on the flat terrace regions of the surface, suggesting the possibility of the fabrication of structured arrays (e.g., chains) of size-selected particles. A theoretical analysis of the particle-particle gap size distribution along the step probes the 1D mobility of the particles trapped at the step. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120719

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The presence of 180° ferroelectric domains in polycrystallineBaTiO3thin films has been observed with the aid of transmission electron microscopy. The 180° domain boundary exhibited a curved appearance, and its orientational relationship was demonstrated. It was found that equiaxial grains did not have 180° domain boundaries due to their higher boundary energy. The grain size effect on dielectric constant of polycrystallineBaTiO3thin films was also discussed in conjunction with 180° ferroelectric domains. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120720

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

It was observed with transmission electron microscopy in theIn0.52Al0.48As/InxGa1−xAs/In0.52Al0.48Assystem grown on the (001) InP substrate that misfit dislocation lines deviate ⟨110⟩ directions at an angle with its value depending on the gallium content. Such an abnormal alignment of misfit dislocations is explained in terms of an alloy effect on the formation of single jogs on misfit dislocations in the interface between the III–V ternary compounds. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120721

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The formation of epitaxial nanotubes (nanoarches) on the surface of hexagonal BN (h-BN) during electron irradiation is reported. In addition to implications in terms of understanding fullerene based structures, we suggest that these act as the nucleation sites for cubic BN (c-BN) growth and may lead to improved film growth. We also report a strong dependence upon the microscope vacuum, which may be critical in understanding irreproducibility in film growth. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120722

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The variation of the relative permittivity of charged dielectrics with trapped charge density has been investigated by a time-resolved current method, in conjunction with a mirror image method employing a scanning electron microscope. The calculation is made by a mathematical expression derived from classical electromagnetic theory. It is found that the relative permittivity of the charged area in the polymethylmethacrylate sample increases with the trapped charge density and saturates at a certain value of the trapped charge density. These observations have been discussed by analogy with the dielectric saturation occurring at a high applied external electric field. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120723

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Three-dimensional Ge islands between 15 and 200 nm in size were found to grow only on Si(111) surface windows in ultrathinSiO2film after Ge deposition and subsequentSiO2decomposition. The size of Ge islands gradually decreased as the Ge thickness decreased. Pseudomorphic two-dimensional Ge layers with the5×5structure formed in surrounding areas of the windows. The windows were produced by selective thermalSiO2decomposition induced by focused electron beam irradiation. These results suggest a new technique for nanometer-scale Ge island fabrication at given points on Si surfaces. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120724

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We report the effects of medium-energy (3.5 keV) electron-beam irradiation ofC60films between 1 and 4 ML thick grown on Si(100)2×1-Hstudied by high-resolution electron energy-loss spectroscopy. Electron irradiation leads primarily to molecular fragmentation. Initially, molecular fragments are discrete, and saturated with hydrogen, but continued irradiation leads to the formation of a disordered material with a graphitic local structure. Experiments performed on a single monolayer ofC60show that under irradiation, fragments can bond to the substrate via displacement or desorption of the hydrogen atoms bonded to the Si substrate. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120725

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The local texture in three types of patterned, thin-film, Al and AlCu interconnections on Si semiconductor devices is investigated by electron backscatter diffraction. Two types of standard planar metal structures were investigated: (1) blanket Al and (2) blanket Al–0.5 wt &percent; Cu on TiN/Ti underlayers. Both were deposited on amorphousSiO2substrates followed by reactive ion etching to define 0.45–10 &mgr;m wide lines and>10×10 &mgr;m2pads. Damascene structures were also investigated in which Al–0.5 wt &percent; Cu films were deposited into preformed Ti-lined amorphousSiO2trenches, 0.3–5.0 &mgr;m wide by 0.4 &mgr;m deep, followed by chemical–mechanical polishing to remove the metal overburden. For these three types of structures, distinctly different behaviors were observed: the two planar metal samples exhibited either little change or a large increase in their (111) fiber texture strength with decreasing linewidth, while the damascene samples showed a marked decrease in the (111) fiber texture with decreasing linewidth and feature size. In addition, a novel trimodal (111) texture distribution was found in 0.3 &mgr;m wide damascene lines in which appreciableTiAl3formed. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120726

出版商:AIP    

年代:1998

数据来源: AIP