Field-directed sputter sharpening for tailored probe materials and atomic-scale lithography

Schmucker, Scott W.; Kumar, Navneet; Abelson, John R.; Daly, Scott R.; Girolami, Gregory S.; Bischof, M.; Jaeger, David L.; Reidy, Richard F.; Gorman, Brian P.; Alexander, Justin; Ballard, Josh B.; Randall, John N.; Lyding, Joseph W.

doi:10.1038/ncomms1907

Cited by 41 publications

(32 citation statements)

References 37 publications

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“…11 However, at HDL voltages below approximately 4.5 V and sufficiently high current, the HDL spot size becomes atomically precise and above a threshold somewhat independent of electron dose. 12 This work shows the formation of spurious DBs formation well outside the primary patterned area during these low voltage processes, 3,[11][12][13][14] an effect that is difficult to observe at higher voltages due to the tails of the high V spot. While much study has been devoted to the role of electron energy transfer in HDL, little has been devoted to the nature of the dissociative reaction products (liberated H) as described here.…”

Section: Introductionmentioning

confidence: 99%

“…At high enough electron doses the center of the spot may become fully exposed so that all of the hydrogen is removed, but above 6 V, there is still generally a halo of partially exposed areas. 7,11 Since this linewidth depends upon electron dose, much of the halo can be attributed to electron stimulation from the STM tip. 11 However, at HDL voltages below approximately 4.5 V and sufficiently high current, the HDL spot size becomes atomically precise and above a threshold somewhat independent of electron dose.…”

Section: Introductionmentioning

confidence: 99%

“…7,11 Since this linewidth depends upon electron dose, much of the halo can be attributed to electron stimulation from the STM tip. 11 However, at HDL voltages below approximately 4.5 V and sufficiently high current, the HDL spot size becomes atomically precise and above a threshold somewhat independent of electron dose. 12 This work shows the formation of spurious DBs formation well outside the primary patterned area during these low voltage processes, 3,[11][12][13][14] an effect that is difficult to observe at higher voltages due to the tails of the high V spot.…”

Section: Introductionmentioning

confidence: 99%

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Spurious dangling bond formation during atomically precise hydrogen depassivation lithography on Si(100): The role of liberated hydrogen

Ballard¹,

Owen²,

Alexander³

et al. 2014

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

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The production of spurious dangling bonds during the hydrogen depassivation lithography process on Si(100)-H is studied. It is shown that the number of spurious dangling bonds produced depends on the size of the primary pattern on the surface, not on the electron dose, indicating that the spurious dangling bonds are formed via an interaction of the liberated hydrogen with the surface. It is also shown that repassivation may occur if hydrogen depassivation lithography is performed near an already patterned area. Finally, it is argued that the product of the interaction is a single dangling bond next to a monohydride silicon on a silicon dimer, with a reaction probability much in excess of that previously observed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spurious dangling bond formation during atomically precise hydrogen depassivation lithography on Si(100): The role of liberated hydrogen

Ballard¹,

Owen²,

Alexander³

et al. 2014

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

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“…Further quantitative refinements to near-field spectroscopy will therefore benefit from the standardization of reproducible probe geometries 61 .…”

Section: The Strongly Resonant Limit: Silicon Carbidementioning

confidence: 99%

Model for quantitative tip-enhanced spectroscopy and the extraction of nanoscale-resolved optical constants

et al. 2014

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Near-field infrared spectroscopy by elastic scattering of light from a probe tip resolves optical contrasts in materials at dramatically sub-wavelength scales across a broad energy range, with the demonstrated capacity for chemical identification at the nanoscale. However, current models of probe-sample near-field interactions still cannot provide a sufficiently quantitatively interpretation of measured near-field contrasts, especially in the case of materials supporting strong surface phonons. We present a model of near-field spectroscopy derived from basic principles and verified by finite-element simulations, demonstrating superb predictive agreement both with tunable quantum cascade laser near-field spectroscopy of SiO2 thin films and with newly presented nanoscale Fourier transform infrared (nanoFTIR) spectroscopy of crystalline SiC. We discuss the role of probe geometry, field retardation, and surface mode dispersion in shaping the measured near-field response. This treatment enables a route to quantitatively determine nano-resolved optical constants, as we demonstrate by inverting newly presented nanoFTIR spectra of an SiO2 thin film into the frequency dependent dielectric function of its mid-infrared optical phonon. Our formalism further enables tipenhanced spectroscopy as a potent diagnostic tool for quantitative nano-scale spectroscopy.

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“…To improve the resolution of the instruments, process development effort will aim to produce sharp tips with improved wear-resistance in a parallel fashion. Fielddependent sputter sharpening and CVD of Hafnium Diboride are likely candidates for tip development [189]. For array operation and enhanced ease-of-use, the instruments should be implemented in a CMOS process that offers through-silicon-vias; such a process would obviate the need for a coarse approach mechanism, permitting the MEMS to be placed directly on a sample.…”

Section: Applications Of Isothermal Scannersmentioning

confidence: 99%

Single‐Chip Scanning Probe Microscopes

Sarkar

Mansour²

2015

Micro‐ and Nanomanipulation Tools

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Scanning probe microscopes (SPMs) are the highest resolution imaging instruments available today and are among the most important tools in nanoscience. Conventional SPMs suffer from several drawbacks owing to their large and bulky construction and to the use of piezoelectric materials. Large scanners have low resonant frequencies that limit their achievable imaging bandwidth and render them susceptible to disturbance from ambient vibrations. Array approaches have been used to alleviate the bandwidth bottleneck; however as arrays are scaled upwards, the scanning speed must decline to accommodate larger payloads. In addition, the long mechanical path from the tip to the sample contributes thermal drift. Furthermore, intrinsic properties of piezoelectric materials result in creep and hysteresis, which contribute to image distortion. The tip-sample interaction signals are often measured with optical configurations that require large free-space paths, are cumbersome to align, and add to the high cost of state-of-the-art SPM systems. These shortcomings have stifled the widespread adoption of SPMs by the nanometrology community. Tiny, inexpensive, fast, stable and independent SPMs that do not incur bandwidth penalties upon array scaling would therefore be most welcome. A method to increase the quality factor (Q-factor) of flexural resonators is introduced. The method relies on an internal energy pumping mechanism that is based on the interplay between electrical, iv mechanical, and thermal effects. To the best of the author's knowledge, the devices that are designed to harness these effects possess the highest electromechanical Qs reported for flexural resonators operating in air; electrically measured Q is enhanced from ~50 to ~50,000 in one exemplary device. A physical explanation for the underlying mechanism is proposed.The design, fabrication, imaging, and tip-based lithographic patterning with the first single-chip Scanning Thermal Microscopes (SThMs) are also presented. In addition to 3 DOF scanning, these devices possess integrated, thermally isolated temperature sensors to detect heat transfer in the tip-sample region.Imaging is reported with thermocouple-based devices and patterning is reported with resistive heater/sensors. An "isothermal electrothermal scanner" is designed and fabricated, and a method to operate it is detailed. The mechanism, based on electrothermal actuation, maintains a constant temperature in a central location while positioning a payload over a range of >35μm, thereby suppressing the deleterious thermal crosstalk effects that have thus far plagued thermally actuated devices with integrated sensors.

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Field-directed sputter sharpening for tailored probe materials and atomic-scale lithography

Cited by 41 publications

References 37 publications

Spurious dangling bond formation during atomically precise hydrogen depassivation lithography on Si(100): The role of liberated hydrogen

Spurious dangling bond formation during atomically precise hydrogen depassivation lithography on Si(100): The role of liberated hydrogen

Model for quantitative tip-enhanced spectroscopy and the extraction of nanoscale-resolved optical constants

Single‐Chip Scanning Probe Microscopes

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