Bridging the length scales between lithographic patterning and self assembly mechanisms in fabrication of semiconductor nanostructure arrays

Hull, R.; Floro, Jerrold A.; Gherasimova, M.; Graham, Jeremy; Gray, Jennifer L.; Portavoce, A.; Ross, Frances M.; Thorp, J. S.

doi:10.1088/1742-6596/209/1/012003

Cited by 6 publications

(4 citation statements)

References 20 publications

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“…The generation of Si-or Ge-QDs with controllable size tunability and arrangement has been the subject of considerable research starting in the 1990s [7,8]. Several approaches have been proposed for the formation of Si-and Ge-QDs, including chemical synthesis, [9] epitaxial growth, [10] deposition followed by post-annealing, [11] lithographic patterning [12], and electrostatic-gate definition based on two-dimensional electron-gas (2DEG) heterostructures [13]. The key to implementing QD devices for practical applications lies in having an unprecedentedly high degree of control over the crystallinity, size, shape, density or number, and spatial location of QDs, all of which are essentially important for optimizing device performance.…”

Section: Fabrication-related Challenges For Si/ge-qdsmentioning

confidence: 99%

The amazing world of self-organized Ge quantum dots for Si photonics on SiN platforms

et al. 2023

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Beginning with our exciting discovery of germanium (Ge) spherical quantum-dot (QD) formation via the peculiar and symbiotic interactions of Si, Ge, and O interstitials, we have embarked on a journey of vigorous exploration, creating unique configurations of self-organized Ge-QDs/Si-containing layers. Our aim is to generate advanced Ge-QD photonic devices, while using standard, mainstream Si processing techniques. This paper summarizes our portfolio of innovative Ge-QD configurations. With emphasis on both controllability and repeatability, we have fabricated size-tunable, spherical Ge-QDs that are placed at predetermined spatial locations within Si-containing layers (SiO2, Si3N4, and Si) using a coordinated combination of lithographic patterning and self-assembled growth. We have successfully exploited the multi-dimensional, parameter spaces of process conditions in combination with layout designs to achieve exquisite control available through the thermal oxidation of lithographically patterned, poly-Si1 − xGex structures in close proximity with Si3N4/Si layers. In so doing, we have gained insight into the growth kinetics and formation mechanisms of self-organized, Ge spherical QDs embedded within SiO2, Si3N4, and Si layers, respectively. Our Ge-QD configurations have opened up a myriad of process/integration possibilities including top-to-bottom evanescent-wave coupling structures for SiN-waveguided Ge-QD photodetectors and Ge-QD light emitters for Si photonics within Si3N4 integrated photonics platforms for on-chip interconnects and sensing.

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Section: Fabrication-related Challenges For Si/ge-qdsmentioning

confidence: 99%

The amazing world of self-organized Ge quantum dots for Si photonics on SiN platforms

et al. 2023

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“…The templating process itself (i.e., the nucleation or trapping mechanism) can take various forms. For example, ultralow dose implantation of 25 kV Ga + ions into Si(100) followed by annealing and molecular beam epitaxy (MBE) of germanium was used to fabricate Ge quantum dots (QDs) by Hull et al [42], and the location of QDs was found to be in strong correlation with the IBL pattern if the annealing conditions were selected carefully in relation to the evolving surface morphology. Other types of QDs, such as InAs and InP on GaAs substrate, and Cu 2 O on SrTiO 3 were also produced by other groups.…”

Section: Nucleation Sites For Directed Self-assembly (Dsa)mentioning

confidence: 99%

Direct-Write Ion Beam Lithography

Joshi‐Imre

Bauerdick

2014

Journal of Nanotechnology

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Patterning with a focused ion beam (FIB) is an extremely versatile fabrication process that can be used to create microscale and nanoscale designs on the surface of practically any solid sample material. Based on the type of ion-sample interaction utilized, FIB-based manufacturing can be both subtractive and additive, even in the same processing step. Indeed, the capability of easily creating three-dimensional patterns and shaping objects by milling and deposition is probably the most recognized feature of ion beam lithography (IBL) and micromachining. However, there exist several other techniques, such as ion implantation- and ion damage-based patterning and surface functionalization types of processes that have emerged as valuable additions to the nanofabrication toolkit and that are less widely known. While fabrication throughput, in general, is arguably low due to the serial nature of the direct-writing process, speed is not necessarily a problem in these IBL applications that work with small ion doses. Here we provide a comprehensive review of ion beam lithography in general and a practical guide to the individual IBL techniques developed to date. Special attention is given to applications in nanofabrication.

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“…One strategy for controlling nanostructure location is to create topological features on the substrate surface at which nanostructures will preferentially nucleate during subsequent growth 3 – 5 . Direct milling with focused ion beams (FIB) is a promising method for such surface templating 6 . The conditions for templating can range from high implanted doses, which mill deep features 7 – 9 into the substrate, to low implanted doses, which either generate subtle changes in the surface topography on the order of a few nanometers or create point defects near the surface 10 – 14 .…”

Section: Introductionmentioning

confidence: 99%

Directed Self-Assembly of Ge Quantum Dots Using Focused Si2+ Ion Beam Patterning

Chee

Kammler

Graham

et al. 2018

Sci Rep

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We show that templating a Si surface with a focused beam of Si2+ or Si+ ions can create suitable nucleation sites for the subsequent growth of self-assembled Ge quantum dots by chemical vapor deposition. To determine the mechanism of patterning we use atomic force microscopy to show that, similar to Ga+ patterning, the formation of a surface pit is required to enable control over Ge quantum dot locations. We find that relatively high implantation doses are required to achieve patterning, and these doses lead to amorphization of the substrate. We assess the degree to which the substrate crystallinity can be recovered by subsequent processing. Using in situ transmission electron microscopy heating experiments we find that recrystallization is possible at the growth temperature of the Ge quantum dots, but defects remain that follow the pattern of the initial implantation. We discuss the formation mechanism of the defects and the benefits of using Si ions for patterning both defects and quantum dots on Si substrates.

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Bridging the length scales between lithographic patterning and self assembly mechanisms in fabrication of semiconductor nanostructure arrays

Cited by 6 publications

References 20 publications

The amazing world of self-organized Ge quantum dots for Si photonics on SiN platforms

The amazing world of self-organized Ge quantum dots for Si photonics on SiN platforms

Direct-Write Ion Beam Lithography

Directed Self-Assembly of Ge Quantum Dots Using Focused Si2+ Ion Beam Patterning

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