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Raffaelle P, Wang GT, Shestopalov AA. Vapor-Phase Halogenation of Hydrogen-Terminated Silicon(100) Using N-Halogen-succinimides. ACS APPLIED MATERIALS & INTERFACES 2023; 15:55139-55149. [PMID: 37965814 PMCID: PMC10694808 DOI: 10.1021/acsami.3c13269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/26/2023] [Accepted: 10/30/2023] [Indexed: 11/16/2023]
Abstract
The focus of this study was to demonstrate the vapor-phase halogenation of Si(100) and subsequently evaluate the inhibiting ability of the halogenated surfaces toward atomic layer deposition (ALD) of aluminum oxide (Al2O3). Hydrogen-terminated silicon ⟨100⟩ (H-Si(100)) was halogenated using N-chlorosuccinimide (NCS), N-bromosuccinimide (NBS), and N-iodosuccinimide (NIS) in a vacuum-based chemical process. The composition and physical properties of the prepared monolayers were analyzed by using X-ray photoelectron spectroscopy (XPS) and contact angle (CA) goniometry. These measurements confirmed that all three reagents were more effective in halogenating H-Si(100) over OH-Si(100) in the vapor phase. The stability of the modified surfaces in air was also tested, with the chlorinated surface showing the greatest resistance to monolayer degradation and silicon oxide (SiO2) generation within the first 24 h of exposure to air. XPS and atomic force microscopy (AFM) measurements showed that the succinimide-derived Hal-Si(100) surfaces exhibited blocking ability superior to that of H-Si(100), a commonly used ALD resist. This halogenation method provides a dry chemistry alternative for creating halogen-based ALD resists on Si(100) in near-ambient environments.
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Affiliation(s)
- Patrick
R. Raffaelle
- Department
of Chemical Engineering, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York 14627, United States
| | - George T. Wang
- Sandia
National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Alexander A. Shestopalov
- Department
of Chemical Engineering, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York 14627, United States
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Dwyer KJ, Baek S, Farzaneh A, Dreyer M, Williams JR, Butera RE. B-Doped δ-Layers and Nanowires from Area-Selective Deposition of BCl 3 on Si(100). ACS APPLIED MATERIALS & INTERFACES 2021; 13:41275-41286. [PMID: 34405671 DOI: 10.1021/acsami.1c10616] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Atomically precise, δ-doped structures forming electronic devices in Si have been routinely fabricated in recent years by using depassivation lithography in a scanning tunneling microscope (STM). While H-based precursor/monatomic resist chemistries for incorporation of donor atoms have dominated these efforts, the use of halogen-based chemistries offers a promising path toward atomic-scale manufacturing of acceptor-based devices. Here, B-doped δ-layers were fabricated in Si(100) by using BCl3 as an acceptor dopant precursor in ultrahigh vacuum. Additionally, we demonstrate compatibility of BCl3 with both H and Cl monatomic resists to achieve area-selective deposition on Si. In comparison to bare Si, BCl3 adsorption selectivity ratios for H- and Cl-passivated Si were determined by secondary ion mass spectrometry depth profiling (SIMS) to be 310(10):1 and 1529(5):1, respectively. STM imaging revealed that BCl3 adsorbed readily on bare Si at room temperature, with SIMS measurements indicating a peak B concentration greater than 1.2(1) × 1021 cm-3 with a total areal dose of 1.85(1) × 1014 cm-2 resulting from a 30 langmuir BCl3 dose at 150 °C. In addition, SIMS showed a δ-layer thickness of ∼0.5 nm. Hall bar measurements of a similar sample were performed at 3.0 K, revealing a sheet resistance of ρ□ = 1.9099(4) kΩ □-1, a hole carrier concentration of p = 1.90(2) × 1014 cm-2, and a hole mobility of μ = 38.0(4) cm2 V-1 s-1 without performing an incorporation anneal. Finally, 15 nm wide B δ-doped nanowires were fabricated from BCl3 and were found to exhibit ohmic conduction. This validates the use of BCl3 as a dopant precursor for atomic-precision fabrication of acceptor-doped devices in Si and enables development of simultaneous n- and p-type doped bipolar devices.
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Affiliation(s)
- Kevin J Dwyer
- Department of Physics, University of Maryland, College Park, Maryland 20742, United States
| | - Sungha Baek
- Department of Physics, University of Maryland, College Park, Maryland 20742, United States
| | - Azadeh Farzaneh
- Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States
| | - Michael Dreyer
- Department of Physics, University of Maryland, College Park, Maryland 20742, United States
| | - James R Williams
- Department of Physics, University of Maryland, College Park, Maryland 20742, United States
| | - Robert E Butera
- Laboratory for Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740, United States
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Frederick E, Dwyer KJ, Wang GT, Misra S, Butera RE. The stability of Cl-, Br-, and I-passivated Si(100)-(2 × 1) in ambient environments for atomically-precise pattern preservation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:444001. [PMID: 34348242 DOI: 10.1088/1361-648x/ac1aa4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
Atomic precision advanced manufacturing (APAM) leverages the highly reactive nature of Si dangling bonds relative to H- or Cl-passivated Si to selectively adsorb precursor molecules into lithographically defined areas with sub-nanometer resolution. Due to the high reactivity of dangling bonds, this process is confined to ultra-high vacuum (UHV) environments, which currently limits its commercialization and broad-based appeal. In this work, we explore the use of halogen adatoms to preserve APAM-derived lithographic patterns outside of UHV to enable facile transfer into real-world commercial processes. Specifically, we examine the stability of H-, Cl-, Br-, and I-passivated Si(100) in inert N2and ambient environments. Characterization with scanning tunneling microscopy and x-ray photoelectron spectroscopy (XPS) confirmed that each of the fully passivated surfaces were resistant to oxidation in 1 atm of N2for up to 44 h. Varying levels of surface degradation and contamination were observed upon exposure to the laboratory ambient environment. Characterization byex situXPS after ambient exposures ranging from 15 min to 8 h indicated the Br- and I-passivated Si surfaces were highly resistant to degradation, while Cl-passivated Si showed signs of oxidation within minutes of ambient exposure. As a proof-of-principle demonstration of pattern preservation, a H-passivated Si sample patterned and passivated with independent Cl, Br, I, and bare Si regions was shown to maintain its integrity in all but the bare Si region post-exposure to an N2environment. The successful demonstration of the preservation of APAM patterns outside of UHV environments opens new possibilities for transporting atomically-precise devices outside of UHV for integrating with non-UHV processes, such as other chemistries and commercial semiconductor device processes.
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Affiliation(s)
- E Frederick
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - K J Dwyer
- Department of Physics, University of Maryland, College Park, MD 20742, United States of America
| | - G T Wang
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - S Misra
- Sandia National Laboratories, Albuquerque, NM 87185, United States of America
| | - R E Butera
- Laboratory for Physical Sciences, 8050 Greenmead Drive, College Park, MD 20740, United States of America
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Chang CY, Lin CY, Lin DS. How dissociated fragments of multiatomic molecules saturate all active surface sites-H 2O adsorption on the Si(100) surface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:404004. [PMID: 34265758 DOI: 10.1088/1361-648x/ac14f7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
A fundamental question for the adsorption of any gas molecule on surfaces is its saturation coverage, whose value can provide a comprehensive examination for the adsorption mechanisms, dynamic and kinetic processes involved in the adsorption processes. This investigation utilizes scanning tunneling microscopy to visualize the H2O adsorption processes on the Si(100) surface with a sub-monolayers (<0.05 ML) of chemically-reactive dangling bonds remaining after exposure to (1) a hydrogen atomic beam, (2) H2O, and (3) Cl2gases at room temperature. In all three cases, each of the remaining isolated single dangling bonds (sDB) adsorb and is passivated by either of the two dissociation fragments, the H or OH radical, to form a surface Si-H and Si-OH species. A new adsorption mechanism, termed 'dissociative and asynchronous chemisorption', is proposed for the observation presented herein. Upon approaching a sDB site, the H2O molecule breaks apart into two fragments. One is chemisorbed to the sDB. The other attaches to the same or the neighboring passivated dimer to form a transition state of surface diffusion, which then diffuses on the mostly passivated surface and is eventually chemisorbed to another reactive site. In other words, the chemisorption reactions of the two fragments after dissociation occur at different and uncorrelated time and places. This adsorption mechanism suggests that a diffusion transition state can be an adsorption product in the first step of the dissociative adsorption processes.
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Affiliation(s)
- Chan-Yuen Chang
- Department of Physics, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Cheng-Yu Lin
- Department of Physics, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Deng-Sung Lin
- Department of Physics, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
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Silva-Quinones D, He C, Butera RE, Wang GT, Teplyakov AV. Reaction of BCl 3 with H- and Cl-terminated Si(1 0 0) as a pathway for selective, monolayer doping through wet chemistry. APPLIED SURFACE SCIENCE 2020; 533:146907. [PMID: 33100450 PMCID: PMC7583461 DOI: 10.1016/j.apsusc.2020.146907] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The reaction of boron trichloride with the H and Cl-terminated Si(100) surfaces was investigated to understand the interaction of this molecule with the surface for designing wet-chemistry based silicon surface doping processes using a carbon- and oxygen-free precursor. The process was followed with X-ray photoelectron spectroscopy (XPS). Within the reaction conditions investigated, the reaction is highly effective on Cl-Si(100) for temperatures below 70°C, at which point both surfaces react with BCl3. The XPS investigation followed the formation of a B 1s peak at 193.5 eV corresponding to (B-O)x species. Even the briefest exposure to ambient conditions lead to hydroxylation of surface borochloride species. However, the Si 2p signature at 102 eV allowed for a confirmation of the formation of a direct Si-B bond. Density functional theory was utilized to supplement the analysis and identify possible major surface species resulting from these reactions. This work provides a new pathway to obtain a functionalized silicon surface with a direct Si-B bond that can potentially be exploited as a means of selective, ultra-shallow, and supersaturated doping.
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Affiliation(s)
- Dhamelyz Silva-Quinones
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716, United States
| | - Chuan He
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716, United States
| | - Robert E. Butera
- Laboratory for Physical Sciences, College Park, Maryland, 20740, United States
| | - George T. Wang
- Sandia National Laboratories, Albuquerque, NM, 87185, United States
| | - Andrew V. Teplyakov
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, 19716, United States
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Dwyer KJ, Dreyer M, Butera RE. STM-Induced Desorption and Lithographic Patterning of Cl–Si(100)-(2 × 1). J Phys Chem A 2019; 123:10793-10803. [DOI: 10.1021/acs.jpca.9b07127] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K. J. Dwyer
- Department of Physics, University of Maryland, College Park, Maryland 20740, United States
| | - Michael Dreyer
- Department of Physics, University of Maryland, College Park, Maryland 20740, United States
| | - R. E. Butera
- Laboratory for Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740, United States
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