摘要:

SiO2thin films were deposited with atomic layer control using binary reaction sequence chemistry. TheSiO2growth was accomplished by separating the binary reactionSiCl4+2H2O→SiO2+4HClinto two half-reactions. Successive application of the half-reactions in an ABAB&ellip; sequence producedSiO2deposition at temperatures between 600 and 800 K and reactant pressures of 1–10 Torr. TheSiO2growth was monitored using ellipsometry versus substrate temperature and reactant exposure time. The maximumSiO2deposition per AB cycle was 1.1 Å/AB cycle at 600 K. The surface topography measured using atomic force microscopy was extremely flat with a roughness nearly identical to the initial substrate. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118494

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Thermal decomposition of ultrathin oxide layers (less than 1 nm thick) on Si(111) surfaces was studied by using scanning reflection electron microscopy and scanning tunneling microscopy. Void formation, where the diameter and density of the voids depend on the oxide film thickness, occurred on terraces randomly and independently of the buried steps atSiO2/Si(111)interfaces. Decomposition of the oxide layers caused by the void growth produced atomic-height holes on exposed Si surfaces. The surface roughness produced by the holes after thermal decomposition increased with the thickness of the oxide layers. The surface mass transport of Si adatoms to form volatile SiO products explains these experimental results. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118495

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The response of TiN/B–C–N multilayers to vacuum annealing at 900 °C and to 300 keV argon irradiation is studied. Changes in composition, stress field, bilayer repeat length, and layered structure are reported. The modifications observed during thermal annealing are mainly related to the departure of nitrogen because of the initial high state of compressive stress. During irradiation, the viscous flow of atoms perpendicular to the stress field causes an increase of the bilayer repeat length and interdiffusion between each layer. This mechanism leads to relaxation of stress and to the disappearance of the layered structure for higher dose. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118496

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

UsingLa0.5Sr0.5CoO3(LSCO) or Pt film as a bottom electrode layer, epitaxialBi4Ti3O12(BTO) thin films were grown on MgO(001) substrates by pulsed laser deposition. A symmetric Pt/BTO/Pt capacitor structure shows a surprisingly large asymmetric polarization switching behavior, but a Pt/BTO/LSCO structure has a nearly symmetricP–Vhysteresis. The strong asymmetric behavior in the Pt/BTO/Pt was attributed to positive charges resulting from interdiffusion at the bottom BTO/Pt interface.P–Vhysteresis studies using numerous top electrode materials and Auger electron spectroscopy depth profile measurement also support formation of interfacial charges. Imprint pulse test shows that such an imprint failure cannot be recovered by applying a dc bias field.©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118497

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Nanostructures consisting ofC60molecules were fabricated on a GaSe/MoS2heterostructure. A submonolayer film of a lamellar compound semiconductor GaSe was grown on aMoS2substrate to form nanoscale holes or grooves surrounded by monolayer steps. Atomic force microscope (AFM) observation indicates thatC60molecules grow only in the bareMoS2nanoregions at a substrate temperature of 180 °C.C60molecules fill up those holes and grooves, and nanoscaleC60domains with polygonal shapes can be formed. This selective growth method can be combined with nanoscale patterning made by a scanning tunneling microscope or AFM to produce nanostructures of molecular crystals with designed shapes.©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118498

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have evaluated an “effective depletion width” of ⩽45 Å and the sign(n-type/upward band bending) of the near surface electric field in low-temperature grown GaAs (001) using the optical method of reflection anisotropy spectroscopy in the vicinity of the spin-orbit splitE1, E1+&Dgr;1optical features. Our results provide evidence that surface Fermi level pinning occurs for air exposed (001) surfaces of undoped low temperature grown GaAs. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118499

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We propose a nanocomposite resist system that incorporates sub-nm carbon particles into a resist film to enable an ultrathin film resist process for nanometer pattern fabrication. Fullerene(C60)is found to be an excellent material for incorporation in view of its etching resistance, dissolution inhibiting effect, molecular size, and composite preparation. A nanocomposite system ofC60and an electron-beam positive resist, ZEP520, show enhancements in both pattern contrast and etching resistance and provide 50 nm patterns in a 50-nm-thick film with a sensitivity of∼50 &mgr;C/cm2.Furthermore, aC60-incorporated chemically amplified resist, SAL601, shows strong environmental stabilization in postexposure delay (<10&percent; after five days) presumably due to the reduction of free volume in the closely packed nanocomposite film. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118500

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have grown by atomic layer epitaxy CdTe/MnTe tilted and serpentine superlattices. These heterostructures are formed by depositing in the step-flow growth mode fractional monolayer superlattices(CdTe)m(MnTe)n,withp=m+n∼1,onto 2 °A and 2 °BCd0.95Zn0.05Tevicinal substrates. Transmission electron microscopy images reveal a good in-plane CdTe/MnTe separation and a uniform short-range superlattice period. The very existence of those superlattices imply that Te-based vicinal surfaces present a regular array of monomolecular steps, with no important step meandering and no step bunching. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118501

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

It is shown that the different and conflicting results on the strength of polarization memory effect on porous Si result from the influence of light on the electrochemical etching process. Illumination in general reduces the memory effect by decreasing the particle shape asymmetry. Linearly polarized light can both enhance or reduce the effect. It is accompanied by an in-plane orientation anisotropy of the memory parameter for (100) porous Si. This effect is evidence for a preferential alignment of the crystallite asymmetry axis normal to the light polarization. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118502

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Data are presented on the laser operation of photoexcited active hexagonal photonic lattices consisting of a GaAs–AlAs superlattice slab waveguide patterned with Zn-disordered AlGaAs posts that are converted to oxide. The semiconductor-oxide-post photonic lattice structure lases without the benefit of cleaved edges or other reflecting interfaces owing to strong local optical feedback provided by the high refractive index contrast between oxide posts and the active GaAs–AlAs superlattice. As the pump area is increased at constant pump power, the threshold intensity decreases as higherQmodes in an effectively larger cavity are excited. Similar hexagonal photonic lattices with nonoxidized posts (disordered AlGaAs posts) operate as lasers, but only with the assistance of cleaved edges and by shifting to longer wavelength. The oxide post photonic lattice is compatible with current-driven photonic lattice lasers or active filters.©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118480

出版商:AIP    

年代:1997

数据来源: AIP