---
_id: '15018'
abstract:
- lang: eng
  text: The epitaxial growth of a strained Ge layer, which is a promising candidate
    for the channel material of a hole spin qubit, has been demonstrated on 300 mm
    Si wafers using commercially available Si0.3Ge0.7 strain relaxed buffer (SRB)
    layers. The assessment of the layer and the interface qualities for a buried strained
    Ge layer embedded in Si0.3Ge0.7 layers is reported. The XRD reciprocal space mapping
    confirmed that the reduction of the growth temperature enables the 2-dimensional
    growth of the Ge layer fully strained with respect to the Si0.3Ge0.7. Nevertheless,
    dislocations at the top and/or bottom interface of the Ge layer were observed
    by means of electron channeling contrast imaging, suggesting the importance of
    the careful dislocation assessment. The interface abruptness does not depend on
    the selection of the precursor gases, but it is strongly influenced by the growth
    temperature which affects the coverage of the surface H-passivation. The mobility
    of 2.7 × 105 cm2/Vs is promising, while the low percolation density of 3 × 1010
    /cm2 measured with a Hall-bar device at 7 K illustrates the high quality of the
    heterostructure thanks to the high Si0.3Ge0.7 SRB quality.
acknowledgement: The Ge project received funding from the European Union's Horizon
  Europe programme under the Grant Agreement 101069515 – IGNITE. Siltronic AG is acknowledged
  for providing the SRB wafers. This work was supported by Imec's Industrial Affiliation
  Program on Quantum Computing.
article_number: '108231'
article_processing_charge: No
article_type: original
author:
- first_name: Yosuke
  full_name: Shimura, Yosuke
  last_name: Shimura
- first_name: Clement
  full_name: Godfrin, Clement
  last_name: Godfrin
- first_name: Andriy
  full_name: Hikavyy, Andriy
  last_name: Hikavyy
- first_name: Roy
  full_name: Li, Roy
  last_name: Li
- first_name: Juan L
  full_name: Aguilera Servin, Juan L
  id: 2A67C376-F248-11E8-B48F-1D18A9856A87
  last_name: Aguilera Servin
  orcid: 0000-0002-2862-8372
- first_name: Georgios
  full_name: Katsaros, Georgios
  id: 38DB5788-F248-11E8-B48F-1D18A9856A87
  last_name: Katsaros
  orcid: 0000-0001-8342-202X
- first_name: Paola
  full_name: Favia, Paola
  last_name: Favia
- first_name: Han
  full_name: Han, Han
  last_name: Han
- first_name: Danny
  full_name: Wan, Danny
  last_name: Wan
- first_name: Kristiaan
  full_name: de Greve, Kristiaan
  last_name: de Greve
- first_name: Roger
  full_name: Loo, Roger
  last_name: Loo
citation:
  ama: Shimura Y, Godfrin C, Hikavyy A, et al. Compressively strained epitaxial Ge
    layers for quantum computing applications. <i>Materials Science in Semiconductor
    Processing</i>. 2024;174(5). doi:<a href="https://doi.org/10.1016/j.mssp.2024.108231">10.1016/j.mssp.2024.108231</a>
  apa: Shimura, Y., Godfrin, C., Hikavyy, A., Li, R., Aguilera Servin, J. L., Katsaros,
    G., … Loo, R. (2024). Compressively strained epitaxial Ge layers for quantum computing
    applications. <i>Materials Science in Semiconductor Processing</i>. Elsevier.
    <a href="https://doi.org/10.1016/j.mssp.2024.108231">https://doi.org/10.1016/j.mssp.2024.108231</a>
  chicago: Shimura, Yosuke, Clement Godfrin, Andriy Hikavyy, Roy Li, Juan L Aguilera
    Servin, Georgios Katsaros, Paola Favia, et al. “Compressively Strained Epitaxial
    Ge Layers for Quantum Computing Applications.” <i>Materials Science in Semiconductor
    Processing</i>. Elsevier, 2024. <a href="https://doi.org/10.1016/j.mssp.2024.108231">https://doi.org/10.1016/j.mssp.2024.108231</a>.
  ieee: Y. Shimura <i>et al.</i>, “Compressively strained epitaxial Ge layers for
    quantum computing applications,” <i>Materials Science in Semiconductor Processing</i>,
    vol. 174, no. 5. Elsevier, 2024.
  ista: Shimura Y, Godfrin C, Hikavyy A, Li R, Aguilera Servin JL, Katsaros G, Favia
    P, Han H, Wan D, de Greve K, Loo R. 2024. Compressively strained epitaxial Ge
    layers for quantum computing applications. Materials Science in Semiconductor
    Processing. 174(5), 108231.
  mla: Shimura, Yosuke, et al. “Compressively Strained Epitaxial Ge Layers for Quantum
    Computing Applications.” <i>Materials Science in Semiconductor Processing</i>,
    vol. 174, no. 5, 108231, Elsevier, 2024, doi:<a href="https://doi.org/10.1016/j.mssp.2024.108231">10.1016/j.mssp.2024.108231</a>.
  short: Y. Shimura, C. Godfrin, A. Hikavyy, R. Li, J.L. Aguilera Servin, G. Katsaros,
    P. Favia, H. Han, D. Wan, K. de Greve, R. Loo, Materials Science in Semiconductor
    Processing 174 (2024).
date_created: 2024-02-22T14:10:40Z
date_published: 2024-02-20T00:00:00Z
date_updated: 2024-02-26T10:36:35Z
day: '20'
ddc:
- '530'
department:
- _id: GeKa
- _id: NanoFab
doi: 10.1016/j.mssp.2024.108231
has_accepted_license: '1'
intvolume: '       174'
issue: '5'
keyword:
- Mechanical Engineering
- Mechanics of Materials
- Condensed Matter Physics
- General Materials Science
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1016/j.mssp.2024.108231
month: '02'
oa: 1
oa_version: Published Version
project:
- _id: 34c0acea-11ca-11ed-8bc3-8775e10fd452
  grant_number: '101069515'
  name: Integrated GermaNIum quanTum tEchnology
publication: Materials Science in Semiconductor Processing
publication_identifier:
  issn:
  - 1369-8001
publication_status: epub_ahead
publisher: Elsevier
quality_controlled: '1'
status: public
title: Compressively strained epitaxial Ge layers for quantum computing applications
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 174
year: '2024'
...
---
APC_amount: '12345'
_id: '14793'
abstract:
- lang: eng
  text: Superconductor/semiconductor hybrid devices have attracted increasing interest
    in the past years. Superconducting electronics aims to complement semiconductor
    technology, while hybrid architectures are at the forefront of new ideas such
    as topological superconductivity and protected qubits. In this work, we engineer
    the induced superconductivity in two-dimensional germanium hole gas by varying
    the distance between the quantum well and the aluminum. We demonstrate a hard
    superconducting gap and realize an electrically and flux tunable superconducting
    diode using a superconducting quantum interference device (SQUID). This allows
    to tune the current phase relation (CPR), to a regime where single Cooper pair
    tunneling is suppressed, creating a sin(2y) CPR. Shapiro experiments complement
    this interpretation and the microwave drive allows to create a diode with ≈ 100%
    efficiency. The reported results open up the path towards integration of spin
    qubit devices, microwave resonators and (protected) superconducting qubits on  the
    same silicon technology compatible platform.
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
acknowledgement: "We acknowledge Alexander Brinkmann, Alessandro Crippa, Francesco
  Giazotto, Andrew Higginbotham, Andrea Iorio, Giordano Scappucci, Christian Schonenberger,
  and Lukas Splitthoff for helpful discussions. We thank Marcel Verheijen for the
  support in the TEM analysis. This research and related results were made possible
  with the support of the NOMIS\r\nFoundation. It was supported by the Scientific
  Service Units of ISTA through resources provided by the MIBA Machine Shop and the
  nanofabrication facility, the European Union’s Horizon 2020 research andinnovation
  programme under Grant Agreement No 862046, the HORIZONRIA\r\n101069515 project,
  the European Innovation Council Pathfinder grant no. 101115315 (QuKiT), and the
  FWF Projects #P-32235, #P-36507 and #F-8606. For the purpose of open access, the
  authors have applied a CC BY public copyright licence to any Author Accepted Manuscript
  version arising from this submission. R.S.S. acknowledges Spanish CM “Talento Program\"\r\nProject
  No. 2022-T1/IND-24070. J.J. acknowledges European Research Council TOCINA 834290."
article_number: '169'
article_processing_charge: Yes
article_type: original
author:
- first_name: Marco
  full_name: Valentini, Marco
  id: C0BB2FAC-D767-11E9-B658-BC13E6697425
  last_name: Valentini
- first_name: Oliver
  full_name: Sagi, Oliver
  id: 71616374-A8E9-11E9-A7CA-09ECE5697425
  last_name: Sagi
- first_name: Levon
  full_name: Baghumyan, Levon
  id: 7aa1f788-b527-11ee-aa9e-e6111a79e0c7
  last_name: Baghumyan
- first_name: Thijs
  full_name: de Gijsel, Thijs
  id: a0ece13c-b527-11ee-929d-bad130106eee
  last_name: de Gijsel
- first_name: Jason
  full_name: Jung, Jason
  id: 4C9ACE7A-F248-11E8-B48F-1D18A9856A87
  last_name: Jung
- first_name: Stefano
  full_name: Calcaterra, Stefano
  last_name: Calcaterra
- first_name: Andrea
  full_name: Ballabio, Andrea
  last_name: Ballabio
- first_name: Juan L
  full_name: Aguilera Servin, Juan L
  id: 2A67C376-F248-11E8-B48F-1D18A9856A87
  last_name: Aguilera Servin
  orcid: 0000-0002-2862-8372
- first_name: Kushagra
  full_name: Aggarwal, Kushagra
  id: b22ab905-3539-11eb-84c3-fc159dcd79cb
  last_name: Aggarwal
  orcid: 0000-0001-9985-9293
- first_name: Marian
  full_name: Janik, Marian
  id: 396A1950-F248-11E8-B48F-1D18A9856A87
  last_name: Janik
- first_name: Thomas
  full_name: Adletzberger, Thomas
  id: 38756BB2-F248-11E8-B48F-1D18A9856A87
  last_name: Adletzberger
- first_name: Rubén
  full_name: Seoane Souto, Rubén
  last_name: Seoane Souto
- first_name: Martin
  full_name: Leijnse, Martin
  last_name: Leijnse
- first_name: Jeroen
  full_name: Danon, Jeroen
  last_name: Danon
- first_name: Constantin
  full_name: Schrade, Constantin
  last_name: Schrade
- first_name: Erik
  full_name: Bakkers, Erik
  last_name: Bakkers
- first_name: Daniel
  full_name: Chrastina, Daniel
  last_name: Chrastina
- first_name: Giovanni
  full_name: Isella, Giovanni
  last_name: Isella
- first_name: Georgios
  full_name: Katsaros, Georgios
  id: 38DB5788-F248-11E8-B48F-1D18A9856A87
  last_name: Katsaros
  orcid: 0000-0001-8342-202X
citation:
  ama: Valentini M, Sagi O, Baghumyan L, et al. Parity-conserving Cooper-pair transport
    and ideal superconducting diode in planar germanium. <i>Nature Communications</i>.
    2024;15. doi:<a href="https://doi.org/10.1038/s41467-023-44114-0">10.1038/s41467-023-44114-0</a>
  apa: Valentini, M., Sagi, O., Baghumyan, L., de Gijsel, T., Jung, J., Calcaterra,
    S., … Katsaros, G. (2024). Parity-conserving Cooper-pair transport and ideal superconducting
    diode in planar germanium. <i>Nature Communications</i>. Springer Nature. <a href="https://doi.org/10.1038/s41467-023-44114-0">https://doi.org/10.1038/s41467-023-44114-0</a>
  chicago: Valentini, Marco, Oliver Sagi, Levon Baghumyan, Thijs de Gijsel, Jason
    Jung, Stefano Calcaterra, Andrea Ballabio, et al. “Parity-Conserving Cooper-Pair
    Transport and Ideal Superconducting Diode in Planar Germanium.” <i>Nature Communications</i>.
    Springer Nature, 2024. <a href="https://doi.org/10.1038/s41467-023-44114-0">https://doi.org/10.1038/s41467-023-44114-0</a>.
  ieee: M. Valentini <i>et al.</i>, “Parity-conserving Cooper-pair transport and ideal
    superconducting diode in planar germanium,” <i>Nature Communications</i>, vol.
    15. Springer Nature, 2024.
  ista: Valentini M, Sagi O, Baghumyan L, de Gijsel T, Jung J, Calcaterra S, Ballabio
    A, Aguilera Servin JL, Aggarwal K, Janik M, Adletzberger T, Seoane Souto R, Leijnse
    M, Danon J, Schrade C, Bakkers E, Chrastina D, Isella G, Katsaros G. 2024. Parity-conserving
    Cooper-pair transport and ideal superconducting diode in planar germanium. Nature
    Communications. 15, 169.
  mla: Valentini, Marco, et al. “Parity-Conserving Cooper-Pair Transport and Ideal
    Superconducting Diode in Planar Germanium.” <i>Nature Communications</i>, vol.
    15, 169, Springer Nature, 2024, doi:<a href="https://doi.org/10.1038/s41467-023-44114-0">10.1038/s41467-023-44114-0</a>.
  short: M. Valentini, O. Sagi, L. Baghumyan, T. de Gijsel, J. Jung, S. Calcaterra,
    A. Ballabio, J.L. Aguilera Servin, K. Aggarwal, M. Janik, T. Adletzberger, R.
    Seoane Souto, M. Leijnse, J. Danon, C. Schrade, E. Bakkers, D. Chrastina, G. Isella,
    G. Katsaros, Nature Communications 15 (2024).
dataavailabilitystatement: All experimental data included in this work are available
  at https://zenodo.org/records/10119346.
date_created: 2024-01-14T23:00:56Z
date_published: 2024-01-02T00:00:00Z
date_updated: 2026-02-26T11:39:00Z
day: '02'
ddc:
- '530'
department:
- _id: GeKa
doi: 10.1038/s41467-023-44114-0
ec_funded: 1
external_id:
  oaworkID:
  - w4390499170
  pmid:
  - '38167818'
file:
- access_level: open_access
  checksum: ef79173b45eeaf984ffa61ef2f8a52ab
  content_type: application/pdf
  creator: dernst
  date_created: 2024-01-17T11:03:00Z
  date_updated: 2024-01-17T11:03:00Z
  file_id: '14825'
  file_name: 2024_NatureComm_Valentini.pdf
  file_size: 2336595
  relation: main_file
  success: 1
file_date_updated: 2024-01-17T11:03:00Z
has_accepted_license: '1'
intvolume: '        15'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
oaworkID: 1
pmid: 1
project:
- _id: 237E5020-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '862046'
  name: TOPOLOGICALLY PROTECTED AND SCALABLE QUANTUM BITS
- _id: 34c0acea-11ca-11ed-8bc3-8775e10fd452
  grant_number: '101069515'
  name: Integrated GermaNIum quanTum tEchnology
- _id: bdc2ca30-d553-11ed-ba76-cf164a5bb811
  grant_number: '101115315'
  name: Quantum bits with Kitaev Transmons
- _id: 237B3DA4-32DE-11EA-91FC-C7463DDC885E
  call_identifier: FWF
  grant_number: P32235
  name: Towards scalable hut wire quantum devices
- _id: bd8bd29e-d553-11ed-ba76-f0070d4b237a
  grant_number: P36507
  name: Merging spin and superconducting qubits in planar Ge
- _id: 34a66131-11ca-11ed-8bc3-a31681c6b03e
  grant_number: F8606
  name: Conventional and unconventional topological superconductors
publication: Nature Communications
publication_identifier:
  eissn:
  - 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Parity-conserving Cooper-pair transport and ideal superconducting diode in
  planar germanium
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 15
year: '2024'
...