摘要:

Ultrafine patterning and metallization technologies have been studied using a combination of refractory metal oxide(MoO3andWO3)resists andGa+focused ion beam lithography. It is demonstrated that, depending on the preparation condition of the films, these thin oxide films act as either a negative or a positive resist with high-contrast capability. As a novel application of this dual-functional behavior, a bilayer resist system using negative(MoO3)and the positive-type(WO3)resists is presented here in order to enhance the high-resolution capability. Based on this technique, nanometer-widthMoO3/WO3line patterns can be delineated onto Si substrates. The delineated line patterns were directly reduced to fine Mo/W wires by heat treatment in a dryH2gas atmosphere. The electrical properties of the Mo/W lines were evaluated in terms of sheet resistance and their temperature dependence. By introduction of the bilayer resist, the sheet resistance of reduced nanowires was significantly decreased in comparison to that of the monolayer case. The usefulness of oxide resists as refractory metal nanowiring has been further increased by employing the bilayer resist system.

ISSN:1071-1023    

DOI:10.1116/1.590269

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

We have prepared a diamond membrane x-ray mask using our novel fabrication techniques which include fluidized bed pretreatment, stress control of diamond film, and chemical-mechanical polishing (CMP), and we have evaluated its important properties for practical use in detail. Surface roughness of diamond film was improved from 55.7 to 1.5 nm Ra using the CMP technique. The transmittance of visible light increased considerably due to the reduction of incident light scattering at the diamond surface, and the transmittance of 2.2-μm-thick smooth diamond film was 92% at 633 nm. In-plane distortion-induced synchrotron radiation irradiation wasMax(x,y)=(13,10) nmwith a dosage of 12.8 kJ/cm2. In final evaluation, that is, of lithographic performance, we confirmed that a 0.2 μm gate array pattern can be successfully transferred.

ISSN:1071-1023    

DOI:10.1116/1.590270

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

The depth resolution and the accuracy of depth calibration in sputter profiling of boron delta distributions in silicon have been investigated using 1 keVO2+ion bombardment at impact angles θ between2°and62°(to the surface normal) in combination with secondary ion mass spectrometry. The effect of jet-type oxygen flooding during sputter erosion was studied at62°.For θ up to34°,the depth resolution was essentially independent of θ (full width at half maximum, FWHM, 2.9 nm, decay length 1.4 nm) and also independent of depth (for deltas located between 40 and 190 nm). However, the well-known peak shift due to the initialshort-termchange in erosion rate was a factor of 2.7 larger at34°than at2°(3.5 vs 1.3 nm). As θ exceeded about36°,two other types of artifacts were observed during bombardment in vacuum, (i) a severe profile broadening and (ii) a largelong-termchange in erosion rate which gave rise to crater-depth dependent peak shifts of the deltas (erosion rate reduced for41°<θ<62°,but enhanced for36°<θ<40°). Both effects became more severe as the sputtered depth became larger. In accordance with the previous surface topography investigations, the observed changes of the matrix ion signals provide evidence for a rapid onset of bombardment induced surface roughening, or ripple formation, starting at depths as low as about 15 nm. The artifacts were most severe at angles between47°and52°,in which case, at a depth of 190 nm, the FWHM increased to as much as 13 nm. In parallel, the erosion rate, averaged over depth intervals of 41–51 nm, decreased continuously by up to 23%. As a result, the 41 nm boron delta appeared to be shifted towards the surface by as much 6 nm. The very large changes in erosion rate invalidate depth calibration procedures based on final crater-depth measurements. At62°,the depth profiling artifacts were significantly enlarged by oxygen flooding, notably at intermediate pressures, at which ripples grew so rapidly that the FWHM of boron deltas located at a depth of only 88 nm amounted to 13 nm. Even at the highest tolerable oxygen pressure(5×10−6 hPa),the FWHM was a factor of about 2 larger than at normal or near-normal beam incidence in vacuum. Furthermore, the decreasing erosion rate gave rise to an apparent 4 nm shift of the 41 nm delta towards the surface. We conclude that 1 keVO2+bombardment at oblique incidence(36°<θ<62°)always gives rise to rapid ripple growth in vacuum and apparently also with oxygen flooding. Accurate depth profiles cannot be obtained under these conditions.

ISSN:1071-1023    

DOI:10.1116/1.590271

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Si0.8Ge0.2strained epilayers were grown on Si substrates by rapid thermal process/very low pressure-chemical vapor deposition and implanted with boron at 40 keV for a dose of2.5×1014cm2.Rapid thermal annealing (RTA) and steady-state furnace annealing with different temperatures and time periods were performed for comparison. Results indicate that RTA is better than furnace annealing. The optimum annealing conditions are RTA at750–850 °Cfor 10 s or at700 °Cfor40–50s. At these conditions the implantation induced damage can be removed; the carrier mobility was about 300cm2/V sand the activity was nearly 100%. The experiments also indicate that a Si cap layer can protect the crystals.

ISSN:1071-1023    

DOI:10.1116/1.590272

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

In order to develop a corrosion-free halogen gas delivery system for use in semiconductor manufacturing,Cr2O3passivation of ferritic and austenitic stainless steels has been investigated. It has been shown that aCr2O3layer can be formed on an electropolished (EP) surface of ferritic 26Cr–1Mo stainless steel by oxidation above 600 °C, but excellent corrosion resistance performance toCl2gas can be obtained only by oxidation above 700 °C. On the other hand, on the EP surface of austenitic SUS 316L, a corrosion-resistantCr2O3layer is not formed by oxidation even up to 800 °C.

ISSN:1071-1023    

DOI:10.1116/1.590273

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

We report the controlled adsorption of individual multi- and single-walled carbon nanotubes from purified aqueous dispersions onto chemically modified silicon oxide surfaces as well as on predefined electrode patterns (100 nm electrode separation). Detailed structural investigations were performed using scanning force microscopy (SFM) without interference from other carbon materials. These studies revealed the striking flexibility of single-walled nanotubes. In contrast to comparably stiff multi-walled nanotubes (MWNTs) which bridged the electrode lines, single-walled nanotubes (SWNTs) were found to follow the profile of the underlying electrodes almost exactly. Based upon the SFM cross sectional analysis of an individual MWNT (8 nm diameter) a Young modulus of about 1 TPa was estimated. Furthermore, nanotube adsorption from the surfactant-stabilized dispersions led to flow-induced orientation processes.

ISSN:1071-1023    

DOI:10.1116/1.590274

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

The fabrication and structural characteristics of ultrathin nanocrystallization silicon films is reported. Amorphous Si layers, with nominal thicknesses in the range of 3.5–11 nm, were deposited by low-pressure chemical vapor deposition onto amorphousSiO2and then crystallized using rapid thermal annealing at temperatures from 650 to 750 °C. High-resolution electron microscopy revealed that the resulting films were comprised almost entirely of Si nanocrystallites with a small fraction of remaining amorphous material. The grain size in the vertical growth direction was controlled by the thickness of the as-deposited amorphous Si film, whereas the lateral grain size was determined by appropriate choice of the annealing conditions.

ISSN:1071-1023    

DOI:10.1116/1.590275

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Formation of silicon nanopillars via selective oxygen etching of Si(111) surface using silicon nitride islands in the initial stage of nitridation was investigated by scanning tunneling microscopy and low energy electron diffraction. Silicon nitride islands with diameters of 6–15 nm, which were formed by low energy nitrogen ions, were resistive toO2exposure at high temperatures resulting in silicon nanopillars as high as 2–3 nm. Existence of high density silicon nitride islands is considered to suppress the step flow etching of nearby silicon surfaces, resulting in a spatially nonuniform etching of silicon.

ISSN:1071-1023    

DOI:10.1116/1.590238

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

An incremental-growth model is described for the deposition of thin dielectric films with spatially modulated columnar nanostructures. Expressions, relating the ratio of the peak-to-peak modulation depth and the spatial wavelength or pitch to extreme deposition angles, are listed for the special cases of sinusoidal modulations in the deposition plane and helical columns that grow normal to the substrate. The deposition of a nanostructure modulated perpendicular to the deposition plane is, as well, demonstrated. In each case simulations made using the model display features that are similar to those shown in scanning electron microscope photographs recorded for fractures in appropriate planes.

ISSN:1071-1023    

DOI:10.1116/1.590276

出版商:American Vacuum Society    

年代:1998

数据来源: AIP

摘要:

Based on our earlier works, 10 nm open windows in theSiO2,Si nanowires, and Ge nanowires were fabricated using electron beam induced selective thermal desorption (EB-STD) ofSiO2on Si substrates. In this article, we show that selective etching can be performed with oxygen gas using anSiO2mask which includes approximately 10-nm-wide open windows formed by STD using focused EB. We also demonstrate the formation of an approximately 10 nm periodic surface structure of Si andSiO2by STD after irradiation with EB interference fringes. The mechanisms related to these techniques are also discussed. These various methods indicate that EB-STD will be useful for fabricating Si structures of the order of 10 nm.

ISSN:1071-1023    

DOI:10.1116/1.590239

出版商:American Vacuum Society    

年代:1998

数据来源: AIP