Si epitaxy on Cl-Si(100)

Farzaneh, Azadeh; Butera, R. E.

doi:10.1016/j.apsusc.2022.152877

Cited by 5 publications

(1 citation statement)

References 68 publications

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“…Samples were chlorinated in situ using a home-built solid-state electrochemical chlorine source based on silver chloride and cadmium chloride. 30,36,37 This source provides precise fluxes of Cl 2 gas molecules, and the corresponding surface coverage on a sample can be calibrated spectroscopically, as briefly described below. The organic compound was degassed by repeated dosing into the chamber, until the mass spectrum showed the expected m/z fragments.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Thermal Atomic Layer Etching Process for 2D van der Waals Material CrPS₄

Piña,

Whalen,

Xiao

et al. 2024

Chem. Mater.

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Preparing two-dimensional (2D) van der Waals materials with atomic-level precision remains a major hurdle, preventing both a number of fundamental explorations of quantum phenomena and a wider range of applications that can be based on a variety of their properties. It is especially challenging for tertiary materials, such as CrPS4, which cannot be produced by controlled deposition but could be managed by etching or thinning in a layer-by-layer approach. Thin flakes of this material can display ferromagnetic or antiferromagnetic behavior depending on the number of layers since the crystal exhibits A-type antiferromagnetic ordering. In order to understand the magnetism down to the monolayer limit and the dynamic excitations in magnons and excitons, and to eventually make devices based on this and similar materials viable, well-controlled layered structures must be produced. The existing methods for controlling CrPS4 thickness, such as mechanical and liquid exfoliation, are not well controlled and are prone to introducing damage to the crystal structure. In this study, we show that thermal atomic layer etching (ALE) can be used to controllably etch the 2D crystals of this material without noticeable contamination. As a starting point, CrPS4 flakes were mechanically exfoliated onto a solid substrate and mounted in an ultra-high vacuum chamber. ALE process consisted of a chlorine gas dose from a solid-state halogen doser followed by exposure to gas-phase acetylacetone (acacH). This ALE approach showed an etch rate of approximately 0.10 nm/cycle at 450 K, confirmed by atomic force microscopy. The etch rate is noticeably faster for the flakes with a large number of defects. The overall process is highly temperature-dependent with a narrow window for successful application.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Thermal Atomic Layer Etching Process for 2D van der Waals Material CrPS₄

Piña,

Whalen,

Xiao

et al. 2024

Chem. Mater.

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Atomistic description of Si etching with HCl

Martinez,

Li,

Prats

et al. 2024

Applied Surface Science

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Bismuth trichloride as a molecular precursor for silicon doping

Lundgren

Conybeare

Stock

et al. 2023

Applied Physics Letters

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Dopant impurity species can be incorporated into the silicon (001) surface via the adsorption and dissociation of simple precursor molecules. Examples include phosphine (PH3), arsine (AsH3), and diborane (B2H6) for the incorporation of phosphorus, arsenic, and boron, respectively. Through exploitation of precursor surface chemistry, the spatial locations of these incorporated dopants can be controlled at the atomic scale via the patterning of a hydrogen lithographic resist layer using scanning tunneling microscopy (STM). There is strong interest in the spatial control of bismuth atoms incorporated into silicon for quantum technological applications; however, there is currently no known precursor for the incorporation of bismuth that is compatible with this STM-based lithographic method. Here, we explore the precursor chemistry (adsorption, diffusion, and dissociation) of bismuth trichloride (BiCl3) on Si(001). We show atomic-resolution STM images of BiCl3 exposed Si(001) surfaces at low coverage and combine this with density functional theory calculations to produce a model of the surface processes and the observed features. Our results show that, at room temperature, BiCl3 completely dissociates to produce bismuth ad-atoms, ad-dimers, and surface-bound chlorine, and we explain how BiCl3 is a strong candidate for a bismuth precursor compound compatible with lithographic patterning at the sub-nanometer scale.

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Si epitaxy on Cl-Si(100)

Cited by 5 publications

References 68 publications

Thermal Atomic Layer Etching Process for 2D van der Waals Material CrPS₄

Thermal Atomic Layer Etching Process for 2D van der Waals Material CrPS₄

Atomistic description of Si etching with HCl

Bismuth trichloride as a molecular precursor for silicon doping

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Si epitaxy on Cl-Si(100)

Cited by 5 publications

References 68 publications

Thermal Atomic Layer Etching Process for 2D van der Waals Material CrPS4

Thermal Atomic Layer Etching Process for 2D van der Waals Material CrPS4

Atomistic description of Si etching with HCl

Bismuth trichloride as a molecular precursor for silicon doping

Contact Info

Product

Resources

About

Thermal Atomic Layer Etching Process for 2D van der Waals Material CrPS₄

Thermal Atomic Layer Etching Process for 2D van der Waals Material CrPS₄