Large Area, 38 nm Half-Pitch Grating Fabrication by Using Atomic Spacer Lithography from Aluminum Wire Grids

Liu, Xiaoming; Deng, Xuegong; Sciortino, P.F.; Buonanno, Mike; Walters, F.S.; Varghese, Ronnie; Bacon, Joel; Chen, Lei; O’Brien, Nada A.; Wang, Jim J.

doi:10.1021/nl061669s

Cited by 35 publications

(34 citation statements)

References 26 publications

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“…In Figure S1(d), a XeF 2 gas phased etch is used to etch the Poly Si only, thus leaving free-standing Al 2 O 3 cylindrical shells on the wafer surface. [23,24,34] Next, in Figure S1 Images of the device during and after fabrication are shown in Figure S2. In Figure S2(a) the photoresist is patterned with a square checkerboard photomask with a period 0.6 µm.…”

Section: Wafer-scale Fabricationmentioning

confidence: 99%

“…[2,22] Photos and SEM images of the 3 device are shown in Figure 1(c)-(f) where the multilayered structure was fabricated using the sidewall lithography technique across a 6" wafer (see supporting information). [23][24][25] cut-off frequency, the design of the cavities is also based on Q-matching formalism where maximum absorption occurs when the radiative Q rad and the absorption Q abs are equal. [22,26] The measured absorption spectrum shown in MDPhC layer agrees well with experiment, but diverges for , where transmission through the metal layer can no longer be assumed to be .…”

mentioning

confidence: 99%

“…[2,22] Photos and SEM images of the device are shown in Figure 1(c)-(f) where the multilayered structure was fabricated using the sidewall lithography technique across a 6" wafer (see supporting information). [23][24][25] An 80 nm thick layer of ruthenium is used as the metal, which was deposited via atomic layer deposition (ALD) for conformal deposition purposes. The dielectric filling of HfO 2 is also deposited via ALD, and excess HfO 2 is removed via chemical mechanical polishing (CMP).…”

mentioning

confidence: 99%

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Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals

Chou¹,

Yeng²,

Lee³

et al. 2014

Advanced Materials

128

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The selective absorption of sunlight plays a critical role in solar-thermophotovoltaic (STPV) energy conversion by tailoring both the absorption and emission spectrums for efficient solar-thermal-electrical energy conversion. [1][2][3][4][5][6][7] By selectively absorbing solar energy while suppressing long wavelength emission, optimal solar-thermal energy conversion can be achieved. In practical STPV systems, selective absorbers must simultaneously contain optical, manufacturing, and reliability properties. Previous efforts have typically focused only on a subset of these requirements. In this communication, we present our solution which contains all of the ideal properties of a selective absorber for large-scale and efficient solar energy conversion.The effective absorption of solar energy requires selective absorption across the solar spectrum, high temperature reliability, omnidirectional absorption, and wafer-scale fabrication 2 for mass scalability. Recent developments of metal based selective absorbers have demonstrated 1D, 2D, and 3D metallic photonic crystal structures capable of tailoring the absorption spectrum. [2,[8][9][10][11][12][13][14] One dimensional metal dielectric stacks have demonstrated promising solar absorbing properties but are unstable at temperatures greater than approximately 600°C. [13] In particular, two-dimensional metallic air photonic crystals (MAPhC) have been shown to selectively absorb light in the near-IR via cavity modes and withstand high temperatures greater than 1000°C; however, the acceptance angle is limited to ±30°, and the absorption in the visible spectrum is limited due to diffraction. [2,11,15] Metamaterial and plasmonic based absorbers have demonstrated wide angle absorption due to their subwavelength periodic structures; however high temperature stability and wafer-scalefabrication have yet to be shown. [1,3,[16][17][18][19] Here we present our 2D metallic dielectric photonic crystal (MDPhC) structure, which simultaneously demonstrates broadband (visible to near-IR) absorption, omnidirectional absorption, wafer-scale fabrication, and high temperature robustness.[20] The wafer-scale fabricated MDPhC has a measured absorption of 85% for photon energies and an absorption below 10% for . Angled measurements show existence of the cavity modes for angles up to 70° from normal. Furnace tests at 1000°C for 24 hours show a robust optical performance due to its fully encapsulated design which helps to retain the metal cavity shapes at high temperatures. [21] Finite-difference time-domain (FDTD) and rigorous coupled wave analysis (RCWA) based simulations indicate that the broadband absorption is due to a high density of hybrid cavity and surface plasmon modes overlaped with an anti-reflection coating (ARC).A schematic image of the MDPhC is shown in Figure 1(a) and (b). The MDPhC utilizes cut-off frequencies of cavity modes to tailor the absorption. Since the cut-off frequency is dependent on the geometry of the cavities, the absorption spectrum can be tuned by simply modif...

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Section: Wafer-scale Fabricationmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals

Chou¹,

Yeng²,

Lee³

et al. 2014

Advanced Materials

128

View full text Add to dashboard Cite

show abstract

“…In the fabrication process, the thickness of the deposited metal layer (30 nm) plays an important role, because it determines the ridge width of the final grating. 20,21 The influence of this effect on the optical performance, namely the extinction ratio of the polarizer, is theoretically calculated for an iridium wire grid polarizer, as shown in Fig. 1(c) and 1(f), and the resist was removed at the final step as shown in Figs.…”

Section: Resultsmentioning

confidence: 99%

Application of double patterning technology to fabricate optical elements: Process simulation, fabrication, and measurement

Babin

Glushenko

Weber

et al. 2012

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Fabrication of ultra-high-density nanodot array patterns (3 Tbits/in.2) using electron-beam lithography J. Vac. Sci. Technol. B 29, 061602 (2011); 10.1116/1.3646469 Catalyst patterning for carbon nanotube growth on elevating posts by self-aligned double-layer electron beam lithography J.Double patterning is an important technique for the improvement of spatial resolution in fabricated micro and nanostructures. In this paper, we investigated and applied the double patterning technique to fabricate diffractive optical elements. Simulations of multiple dry etch and film deposition steps were performed to study and optimize the vertical profiles of the fabricated patterns. Etch and deposition characteristics were varied to study their impact on the resulting vertical profile of the metal layers. The influence of the linewidth of the initial resist pattern and the process-induced tapering of the grating tops on the optical performance were investigated in particular. A variably shaped electron-beam lithography system was used for the fabrication of the initial resist pattern. The spatial frequency was then doubled by means of double patterning. Broadband aluminum and iridium wire grid polarizers were fabricated for applications down to the UV range with a feature size of 30 nm, a period of 100 nm, and a vertical aspect ratio of about 5:1. Optical measurements have confirmed the designed optical properties.

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“…Wire grid polarizers are well known for their capabilities to generate linearly polarized light from non-polarized light in very broad wavelength ranges [32][33][34][35][36]. Previous studies have shown that spatially non-uniform polarization directions can be generated by using curvilinear nanoslits in Ag films [37].…”

Section: Design and Simulations Of Nanoslit-based Pmmsmentioning

confidence: 99%

Designs of Plasmonic Metamasks for Photopatterning Molecular Orientations in Liquid Crystals

et al. 2016

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Aligning liquid crystal (LC) molecules into spatially non-uniform orientation patterns is central to the functionalities of many emerging LC devices. Recently, we developed a new projection photopatterning technique by using plasmonic metamasks (PMMs), and demonstrated high-resolution and high-throughput patterning of molecular orientations into arbitrary patterns. Here we present comparisons between two different types of metamask designs: one based on curvilinear nanoslits in metal films; the other based on rectangular nanoapertures in metal films. By using numerical simulations and experimental studies, we show that the PMMs based on curvilinear nanoslits exhibit advantages in their broadband and high optical transmission, while face challenges in mask designing for arbitrary molecular orientations. In contrast, the PMMs based on nanoapertures, though limited in optical transmission, present the great advantage of allowing for patterning arbitrary molecular orientation fields.

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Large Area, 38 nm Half-Pitch Grating Fabrication by Using Atomic Spacer Lithography from Aluminum Wire Grids

Cited by 35 publications

References 26 publications

Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals

Enabling Ideal Selective Solar Absorption with 2D Metallic Dielectric Photonic Crystals

Application of double patterning technology to fabricate optical elements: Process simulation, fabrication, and measurement

Designs of Plasmonic Metamasks for Photopatterning Molecular Orientations in Liquid Crystals

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