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1.
Nanotechnology ; 25(23): 235305, 2014 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-24850475

RESUMO

We present fabrication and characterization of high-resolution and nearly amorphous Mo1 - xNx transmission gratings and their use as masks for extreme ultraviolet (EUV) interference lithography. During sputter deposition of Mo, nitrogen is incorporated into the film by addition of N2 to the Ar sputter gas, leading to suppression of Mo grain growth and resulting in smooth and homogeneous thin films with a negligible grain size. The obtained Mo0.8N0.2 thin films, as determined by x-ray photoelectron spectroscopy, are characterized to be nearly amorphous using x-ray diffraction. We demonstrate a greatly reduced Mo0.8N0.2 grating line edge roughness compared with pure Mo grating structures after e-beam lithography and plasma dry etching. The amorphous Mo0.8N0.2 thin films retain, to a large extent, the benefits of Mo as a phase grating material for EUV wavelengths, providing great advantages for fabrication of highly efficient diffraction gratings with extremely low roughness. Using these grating masks, well-resolved dense lines down to 8 nm half-pitch are fabricated with EUV interference lithography.

2.
Nanoscale ; 7(9): 4031-7, 2015 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-25653148

RESUMO

All nanofabrication methods come with an intrinsic resolution limit, set by their governing physical principles and instrumentation. In the case of extreme ultraviolet (EUV) lithography at 13.5 nm wavelength, this limit is set by light diffraction and is ≈3.5 nm. In the semiconductor industry, the feasibility of reaching this limit is not only a key factor for the current developments in lithography technologies, but also is an important factor in deciding whether photon-based lithography will be used for future high-volume manufacturing. Using EUV-interference lithography we show patterning with 7 nm resolution in making dense periodic line-space structures with 14 nm periodicity. Achieving such a cutting-edge resolution has been possible by integrating a high-quality synchrotron beam, precise nanofabrication of masks, very stable exposures instrumentation, and utilizing effective photoresists. We have carried out exposure on silicon- and hafnium-based photoresists and we demonstrated the extraordinary capability of the latter resist to be used as a hard mask for pattern transfer into Si. Our results confirm the capability of EUV lithography in the reproducible fabrication of dense patterns with single-digit resolution. Moreover, it shows the capability of interference lithography, using transmission gratings, in evaluating the resolution limits of photoresists.

3.
Nat Commun ; 3: 1096, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23033072

RESUMO

Strained Si nanowires are among the most promising transistor structures for implementation in very large-scale integration due to of their superior electrostatic control and enhanced transport properties. Realizing even higher strain levels within such nanowires are thus one of the current challenges in microelectronics. Here we achieve 4.5% of elastic strain (7.6 GPa uniaxial tensile stress) in 30 nm wide Si nanowires, which considerably exceeds the limit that can be obtained using SiGe-based virtual substrates. Our approach is based on strain accumulation mechanisms in suspended dumbbell-shaped bridges patterned on strained Si-on-insulator, and is compatible with complementary metal oxide semiconductor fabrication. Potentially, this method can be applied to any tensile prestrained layer, provided the layer can be released from the substrate, enabling the fabrication of a variety of strained semiconductors with unique properties for applications in nanoelectronics, photonics and photovoltaics. This method also opens up opportunities for research on strained materials.


Assuntos
Nanotecnologia/métodos , Nanofios/química , Silício/química , Técnicas In Vitro , Resistência à Tração
4.
Adv Mater ; 17(11): 1398-1401, 2005 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-34412443

RESUMO

Chemical nanopatterns down to 50 nm in feature size have been fabricated via nanoimprint lithography and used to simultaneously control azimuthal and polar orientation of liquid crystals (LCs). The polar orientation depends on the ratio of the homeotropic/planar surface potential areas, while the LC azimuthally orients along the direction of the silane patterns.

5.
Appl Opt ; 39(31): 5806-10, 2000 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-18354582

RESUMO

A mechanical method of flattening the Gaussian intensity distribution of laser beams in time average is presented. Specially shaped rotating shutters are the key feature of this method, which has been applied to achieve homogeneous submicrometer patterning of macroscopically large samples by laser interference exposure. This method represents a simple yet useful alternative to applying beam broadening or degaussing plates (apodizing filters).

6.
Langmuir ; 20(9): 3495-7, 2004 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-15875370

RESUMO

We describe a simple method for patterning biomolecular films on surfaces with high resolution. A conventional polymeric resist is structured by electron-beam lithography. The exposed and developed patterns are then used for the directed self-assembly (SA) of a first molecule from solution. Removal of the remaining resist allows the SA of a second species. We illustrate the potential of the approach by assembling on gold (Au) substrates two alkanethiols of contrasting terminal functionality. The patterns have dimensions from the micrometer range down to 40 nm and an edge resolution of 3.5 nm.

7.
Ultramicroscopy ; 82(1-4): 69-77, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10741654

RESUMO

Finite element analysis (FEA) is used to study the effect of geometric variations on the properties of rectangular cantilevers and U-shaped Joule-heated cantilevers. Simulations of locally thinned cantilevers as well as of cantilevers modified by the implementing of a hole or a side cut are compared with fabricated cantilevers, which are tuned by focused ion beam (FIB) milling. By locally thinning the cantilevers, the resonance frequency and the spring constant are reduced. For a hole, the internal stress is increased while for a side cut, the lateral spring constant is decreased. Good agreement between the measured and the simulated resonance frequencies is observed. Simulations of the current density and the temperature distributions attained during the passage of current through a doped silicon layer are performed to optimize the design of Joule-heated cantilevers (U-shaped) for thermal gravimetric applications. A very uniform temperature distribution over a region near the apex can be realized by slitting the U-shaped cantilever. In such a way, the heating power can be minimized by effecting only a small variation in the geometry of a U-shaped cantilever. A simple fabrication process for the fabrication of Joule-heated cantilevers is presented, which consists mainly of a uniform conductive p-doped layer.

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