ORCID Profile
0000-0003-4164-362X
Current Organisation
University College London
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: AIP Publishing
Date: 10-04-2023
DOI: 10.1063/5.0145772
Abstract: Dopant impurity species can be incorporated into the silicon (001) surface via the adsorption and dissociation of simple precursor molecules. Ex les 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.
Publisher: Wiley
Date: 19-07-2023
Abstract: Two‐dimensional dopant layers (δ‐layers) in semiconductors provide the high‐mobility electron liquids (2DELs) needed for nanoscale quantum‐electronic devices. Key parameters such as carrier densities, effective masses, and confinement thicknesses for 2DELs have traditionally been extracted from quantum magnetotransport. In principle, the parameters are immediately readable from the one‐electron spectral function that can be measured by angle‐resolved photoemission spectroscopy (ARPES). Here, buried 2DEL δ‐layers in silicon are measured with soft X‐ray (SX) ARPES to obtain detailed information about their filled conduction bands and extract device‐relevant properties. This study takes advantage of the larger probing depth and photon energy range of SX‐ARPES relative to vacuum ultraviolet (VUV) ARPES to accurately measure the δ‐layer electronic confinement. The measurements are made on ambient‐exposed s les and yield extremely thin ( 1 nm) and dense (≈10 14 cm −2 ) 2DELs. Critically, this method is used to show that δ‐layers of arsenic exhibit better electronic confinement than δ‐layers of phosphorus fabricated under identical conditions.
Publisher: American Chemical Society (ACS)
Date: 06-03-2020
Publisher: American Chemical Society (ACS)
Date: 14-08-2023
Publisher: American Association for the Advancement of Science (AAAS)
Date: 02-06-2017
Abstract: Microwave microscopy enables three-dimensional characterization of atomically thin semiconductor structures with nanometer precision.
Publisher: Springer Science and Business Media LLC
Date: 27-07-2020
Publisher: Wiley
Date: 10-01-2023
Abstract: Germanium has emerged as an exceptionally promising material for spintronics and quantum information applications, with significant fundamental advantages over silicon. However, efforts to create atomic‐scale devices using donor atoms as qubits have largely focused on phosphorus in silicon. Positioning phosphorus in silicon with atomic‐scale precision requires a thermal incorporation anneal, but the low success rate for this step has been shown to be a fundamental limitation prohibiting the scale‐up to large‐scale devices. Here, we present a comprehensive study of arsine (AsH 3 ) on the germanium (001) surface. We show that, unlike any previously studied dopant precursor on silicon or germanium, arsenic atoms fully incorporate into substitutional surface lattice sites at room temperature. Our results pave the way for the next generation of atomic‐scale donor devices combining the superior electronic properties of germanium with the enhanced properties of arsine/germanium chemistry that promises scale‐up to large numbers of deterministically placed qubits.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 21-04-2023
Abstract: In this work, we show the feasibility of extreme ultraviolet (EUV) patterning on an HF-treated silicon (100) surface in the absence of a photoresist. EUV lithography is the leading lithography technique in semiconductor manufacturing due to its high resolution and throughput, but future progress in resolution can be h ered because of the inherent limitations of the resists. We show that EUV photons can induce surface reactions on a partially hydrogen-terminated silicon surface and assist the growth of an oxide layer, which serves as an etch mask. This mechanism is different from the hydrogen desorption in scanning tunneling microscopy–based lithography. We achieve silicon dioxide/silicon gratings with 75-nanometer half-pitch and 31-nanometer height, demonstrating the efficacy of the method and the feasibility of patterning with EUV lithography without the use of a photoresist. Further development of the resistless EUV lithography method can be a viable approach to nanometer-scale lithography by overcoming the inherent resolution and roughness limitations of photoresist materials.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Taylor Stock.