Nanoscale patterning and selective chemistry of silicon surfaces by ultrahigh-vacuum scanning tunneling microscopy

Lyding, Joseph W.; Shen, T. C.; Abeln, G. C.; Wang, C.; Tucker, J. R.

doi:10.1088/0957-4484/7/2/006

Cited by 24 publications

(21 citation statements)

References 22 publications

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“…We start with a discussion of silicon DBs, which are well-studied unterminated silicon atoms [ 52 – 54 ]. In STM, the centre of a DB is imaged as a bright protrusion due to its conductive orbital which extends into vacuum.…”

Section: Resultsmentioning

confidence: 99%

Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

Croshaw

Dienel

Huff

et al. 2020

Beilstein J. Nanotechnol.

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The combination of scanning tunnelling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) allows enhanced extraction and correlation of properties not readily available via a single imaging mode. We demonstrate this through the characterization and classification of several commonly found defects of the hydrogen-terminated silicon (100)-2 × 1 surface (H–Si(100)-2 × 1) by using six unique imaging modes. The H–Si surface was chosen as it provides a promising platform for the development of atom scale devices, with recent work showing their creation through precise desorption or placement of surface hydrogen atoms. While samples with relatively large areas of the H–Si surface are routinely created using an in situ methodology, surface defects are inevitably formed reducing the area available for patterning. By probing the surface using the different interactivity afforded by either hydrogen- or silicon-terminated tips, we are able to extract new insights regarding the atomic and electronic structure of these defects. This allows for the confirmation of literature assignments of several commonly found defects, as well as proposed classifications of previously unreported and unassigned defects. By combining insights from multiple imaging modes, better understanding of their successes and shortcomings in identifying defect structures and origins is achieved. With this, we take the first steps toward enabling the creation of superior H–Si surfaces through an improved understanding of surface defects, ultimately leading to more consistent and reliable fabrication of atom scale devices.

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Section: Resultsmentioning

confidence: 99%

Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

Croshaw

Dienel

Huff

et al. 2020

Beilstein J. Nanotechnol.

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“…H-Si was first identified as an attractive candidate for nanoscale patterning by Lyding et al 30 . Only recently have capabilities reached the levels necessary to enable prototyping of structures on this surface.…”

mentioning

confidence: 99%

Binary atomic silicon logic

et al. 2018

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It has long been anticipated that the ultimate in miniature circuitry will be crafted of single atoms. Despite many advances made in scanned probe microscopy studies of molecules and atoms on surfaces, challenges with patterning and limited thermal stability have remained.Here we make progress toward those challenges and demonstrate rudimentary circuit elements through the patterning of dangling bonds on a hydrogen-terminated silicon surface. Dangling bonds sequester electrons both spatially and energetically in the bulk band gap, circumventing short-circuiting by the substrate. We deploy paired dangling bonds occupied by one moveable electron to form a binary electronic building block.Inspired by earlier quantum dot-based approaches, binary information is encoded in the electron position allowing demonstration of a "binary wire" and an OR gate.The prospect of atom scale computing was initially indicated by "molecular cascades"where sequentially toppling molecules were arranged in precise configurations to achieve binary logic functions 1 . Many notable approaches toward molecular electronics 2-7 , atomic electronics 8,9 , and quantum-dot-based electronics 10-15 have also been explored.The quantum dot based approaches [16][17][18][19][20] are particularly attractive, as they provide a low power yet fast basis 21 to go beyond today's CMOS technology 22 . These approaches, however, require cryogenic temperatures to minimize the population of thermally-excited states and achieve the desired functionality. Variability among quantum dots and sensitivity to uncontrolled fields are

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“…14,15,16 In addition to providing electrical contrast, HDL can introduce chemical contrast on the surface where the passivating H layer has been removed, in effect creating a template for further chemical modification. This chemical modification has been demonstrated on silicon and other surfaces, showing selectivity for deposition of metals, 17 insulators, 18 and even semiconductors. 16,19 Each of these examples produces two dimensional structures, so other processing steps must be used to produce true three dimensional structures with the atomically resolved control promised by HDL.…”

Section: Introductionmentioning

confidence: 98%

Atomically Traceable Nanostructure Fabrication

Ballard

Dick

McDonnell

et al. 2015

JoVE

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Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

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Nanoscale patterning and selective chemistry of silicon surfaces by ultrahigh-vacuum scanning tunneling microscopy

Cited by 24 publications

References 22 publications

Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

Binary atomic silicon logic

Atomically Traceable Nanostructure Fabrication

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