摘要:

When fabricating microscopic features inSiO2layers using low pressure, high-density fluorocarbon plasmas, microtrenching has commonly been observed. Microtrenching has been explained either as due to ion scattering from sloped sidewalls or negative charging of the sidewalls by electrons, and the influence of the associated electric field on ion trajectories. In this work, we show that a weak magnetic field produces a significant asymmetry in microtrenching. Our results demonstrate unambiguously that electron-based sidewall charging is to a significant extent responsible for microtrenching, and, more generally, that differential charging is an important effect in microstructure fabrication using high-density plasmas. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121068

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Electromigration-induced stress distributions in 200 &mgr;m long, 10 &mgr;m wide aluminum conductor lines in 1.5 &mgr;mSiO2passivation layers have been investigated in real time using synchrotron-based white-beam x-ray microdiffraction. The results show that a steady-state linear stress gradient along the length of the line developed within the first few hours of electromigration and that the stress gradient could be manipulated by controlling the magnitude and the direction of the current flow. From the current density dependence of the steady-state stress gradient, the effective valenceZ*was determined to be 1.6 at 260 °C. From the time dependence of the transient-state stress gradient, the effective grain boundary diffusion coefficientDeffwas estimated to be8.2×10−11 cm2/sat 260 °C using Korhonen’s stress evolution model [M. A. Korhonen, P. Bo&slash;rgesen, K. N. Tu, and C.-Y. Li, J. Appl. Phys.73, 3790 (1993)]. BothZ*andDeffvalues are in good agreement with the previously reported values. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120604

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

A technique that excites a localized plasmon on the apex of probe for near-field optical microscope and spectroscope is presented. Vapor deposition and heating of several tens nm thick gold films on 1 nm thick germanium-covered tapered optical fiber probe make highly adherent and smooth overlayers. A “tunneling-photon-mode” experimental system combined with a dye laser is used to excite a localized plasmon. The enhancement of near-field intensity was measured varying incident photon energies with its maximum occurring at 2.11 eV. This local field enhancement could be estimated to generate only in the close proximity of the substrate. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121031

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We have explored the application of chemical derivatives ofC60as high-resolution electron beam resists. Facile spin coating was used to produce∼100-nm-thick films of aC60tris adduct (three functional groups) on Si surfaces. We find that these films function as high-resolution negative resists for electron beam lithography using monochlorobenzene as a developer. The film has a sensitivity of∼1 mC/cm2for 20 keV electrons, an order of magnitude higher than that ofC60itself, and the dry-etch durability is much better than that of conventional novolac based electron beam resists. Features with widths of 20 nm were produced. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120978

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

We have performed calorimetric measurements on 200 nm thin silicon nitride membranes at temperatures from 0.07 to 1 K. Besides full windows, membranes cut into a thermally isolating suspended bridge geometry were investigated. Based on dc and ac measurements employing normal-metal/insulator/superconductor (NIS) tunnel junctions both as a thermometer and a heater, we report on heat transport and thermal relaxation in silicon nitride films. The bridge structure improves thermal isolation and, consequently, energy sensitivity by two orders of magnitude over those of the full membrane with the same size, and makes such a structure very attractive for bolometric and microrefrigeration applications. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120979

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

A low temperature oxygen/nitrogen plasma process is reported that substantially reduces leakage currents in chemical vapor deposited (CVD) and physical vapor deposited (PVD) films of tantalum oxide. We show that a combination of nitrogen and oxygen in a remote downstream microwave plasma source reduces leakage currents in CVD films of tantalum oxide and also reduces trap densities as measured by charge pumping. The as deposited CVD films show a high level of photoluminescence that is substantially lowered by the plasma anneal due to a reduction in the density of midgap states. For films deposited by PVD in the thickness range of 100 nm we find low leakage currents with a substantial improvement from the introduction of nitrogen into the plasma. However, PVD films in the thickness range of 20 nm show larger relative leakage currents and less of an improvement from the addition of nitrogen. The role of nitrogen in lowering leakage currents and charge trapping is thought to occur from a reduction in the density of bulk trap states in the oxide due to partial incorporation of nitrogen in the oxide. Both of these low temperature deposition and annealing processes are compatible with integration into the upper levels of metallization for high density circuits.©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120569

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Polyquinoline/bismaleimide composites containing bismaleimide contents between 5 and 50 wt &percent; have been investigated as high-temperature-resistant materials. The effect of bismaleimide loading on thermal, mechanical, and dielectric properties of polyquinoline has been reported. The dielectric constant of composite thin films was found to vary between 2.90 and 3.10 with the loss tangent ranging between 0.004 and 0.007, depending upon the incorporated bismaleimide content. The thermal, mechanical, and dielectric properties of polyquinoline/bismaleimide composite thin films are discussed. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121683

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Highly tetrahedral hydrogenated amorphous carbon (ta-C:H) is deposited with a novel, 13.6 MHz excited electron cyclotron wave resonance (ECWR) plasma source. The ion flux of an acetylene and a nitrogen plasma was investigated by mass spectrometry and retarding field measurements. The ECWR gives a dissociation degree between 15&percent; and 80&percent; depending on gas flow rate. Ion current densities up to2 mA/cm2can be achieved, corresponding tota-C:H deposition rates of 2 nm/s. The fraction ofsp3bonded carbon atoms and mass density are strongly related to the amount of hydrogen in the ion flux. For low hydrogen ion fluxes (10&percent;), asp3fraction of 70&percent; and a mass density of2.85 g/cm3can be achieved. At higher hydrogen ion fluxes (40&percent;), thesp3fraction and the mass density fall to 55&percent; and2.55 gm/cm3,respectively. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121069

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The quality of lattice-matchedZnxCdyMg1−x−ySeepitaxial layers grown on (001) InP substrates with a III-V buffer layer has been improved by initially growing a ZnCdSe interfacial layer (50 Å) at low temperature. The widths of double crystal x-ray rocking curves forZnxCdyMg1−x−ySeepilayers with band gaps as high as 3.05 eV were reduced to about 70 arcsec. The defect density evaluated from etch pit density and plan-view transmission electron microscopy measurements was reduced by two orders of magnitude, to106–107 cm−2.The photoluminescence band edge emission became more symmetric and slightly narrower. It is proposed that an initial two-dimensional growth mode has been achieved by incorporating such a lattice-matched ZnCdSe layer. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120980

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Photoluminescence peak energy shifts under applied [110] and [100] uniaxial stress are interpreted within the framework of a multi-band Kohn–Luttinger model which takes into account the mixing of heavy, light, and spin-orbit split-off holes within the valence band. Experimental data are presented for 0.5&percent;, 1&percent;, and 1.7&percent;Si1−yCy/Sisamples which are best fitted with a conduction band offset of approximately 70&percent;. At this value of the conduction band offset, we show that small amounts of space charge induced band bending are required to explain the experimentally observed results. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120981

出版商:AIP    

年代:1998

数据来源: AIP