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arxiv: 2605.17192 · v1 · pith:7TOJA3PInew · submitted 2026-05-16 · ⚛️ physics.ins-det

Development of Segmented 4H-SiC LGADs

Vojt\v{e}ch Kr\'a\v{c}mar , Jan Chochol , Adam Klimsza , Jana Koz\'akov\'a , Adam Kozelsky , Ji\v{r}\'i Kroll , Adela Kubr\'anska , M\'aria Mar\v{c}i\v{s}ovsk\'a
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Marcela Mike\v{s}t\'ikov\'a Radek Novotn\'y Aymeric Privat Peter Slov\'ak Tobi\'a\v{s} Vasiljev Peter \v{S}vihra
This is my paper

Pith reviewed 2026-05-20 13:42 UTC · model grok-4.3

classification ⚛️ physics.ins-det
keywords 4H-SiCLGADsegmented detectorsstrip detectorspixel detectorsTPA-TCTradiation hardnessavalanche gain
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The pith

The first segmented 4H-SiC LGAD devices demonstrate functional charge separation with internal gain between adjacent channels.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This work fabricates and tests the initial segmented versions of 4H-SiC low-gain avalanche detectors, extending earlier single-pad prototypes to strips and pixels. The devices use geometric gaps and oxide-filled trenches to isolate channels while retaining the avalanche multiplication that boosts the small charge signals native to SiC. Two-photon absorption transient current measurements at ELI ERIC confirm that signals remain distinct across neighboring strips and pixels yet still exhibit the expected internal gain. If the segmentation holds, these detectors could supply both spatial resolution and radiation hardness for tracking in environments too extreme for conventional silicon sensors.

Core claim

The central claim is that segmented 4H-SiC LGAD strip detectors at 80 micrometer pitch and pixel arrays at 55 and 110 micrometer pitch have been successfully produced by ion implantation, with multiple isolation schemes, and that TPA-TCT scans show clear charge separation accompanied by avalanche gain in the first devices of this kind.

What carries the argument

Inter-channel isolation via geometric separation and oxide-filled trenches that divide the LGAD gain layer into independent readout elements while preserving avalanche multiplication and charge collection in 4H-SiC.

If this is right

  • Spatial segmentation now becomes available on top of the radiation hardness and thermal stability already shown in single-pad 4H-SiC LGADs.
  • Strip and pixel pitches of 80, 55, and 110 micrometers establish that the fabrication process supports multiple readout geometries.
  • The combination of gain and channel isolation opens the possibility of position-sensitive detectors for high-radiation particle tracking.
  • Multiple isolation strategies tested in parallel provide design choices for balancing crosstalk against fill factor.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Further refinement of trench depth or oxide thickness could reduce any residual crosstalk while keeping gain intact.
  • The same segmentation approach may be tested in other wide-bandgap materials where charge generation is also low.
  • Long-term irradiation campaigns would be needed to confirm that the isolation structures remain stable after exposure.
  • Integration with fast readout electronics could be explored to exploit the timing properties of the LGAD gain in segmented format.

Load-bearing premise

The chosen isolation methods keep crosstalk low enough that signals from adjacent channels stay distinguishable without reducing the internal gain or collection efficiency.

What would settle it

Observation of large signal sharing or loss of avalanche gain in TPA-TCT scans across neighboring strips or pixels would show that the segmentation has failed.

read the original abstract

The wide-bandgap semiconductor 4H-silicon carbide (4H-SiC) offers a compelling combination of radiation hardness, thermal stability, and high critical electric field for particle detection in harsh environments. To compensate for the comparatively low charge generation in SiC, the Low-Gain Avalanche Detector (LGAD) concept can be adopted to provide internal signal amplification. Building on three preceding generations of single-pad 4H-SiC LGAD prototypes fabricated by ion implantation, this work presents the design, fabrication, and initial characterization of segmented 4H-SiC LGAD devices -- the first fabricated and characterized devices reported. Strip detectors with 80~$\mu$m pitch and pixel arrays with 55 and 110~$\mu$m pitch were produced using multiple inter-channel isolation strategies, including geometric separation and oxide-filled trenches. Two-photon absorption transient current technique (TPA-TCT) measurements performed at ELI ERIC demonstrate clear charge separation between adjacent strips with internal gain, confirming functional segmentation.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 1 minor

Summary. The manuscript reports the design, fabrication, and initial TPA-TCT characterization of the first segmented 4H-SiC LGAD devices. Strip detectors (80 μm pitch) and pixel arrays (55 and 110 μm pitch) were produced with geometric separation and oxide-filled trenches for inter-channel isolation. The central claim is that these devices exhibit clear charge separation between adjacent strips together with internal avalanche gain, thereby demonstrating functional segmentation.

Significance. If the quantitative performance metrics hold, the work is significant as the first experimental realization of segmented LGADs in 4H-SiC. It extends prior single-pad SiC LGAD prototypes to position-sensitive formats while retaining the radiation hardness and thermal stability advantages of the wide-bandgap material, which is relevant for detectors in high-radiation or high-temperature environments.

major comments (1)
  1. [Abstract / TPA-TCT results] Abstract and Results section on TPA-TCT: the demonstration of 'clear charge separation ... with internal gain' is presented only qualitatively. No extracted values are given for inter-strip crosstalk (e.g., ratio of induced charge on the adjacent channel when the laser is focused on one strip) or for the multiplication factor relative to the preceding single-pad 4H-SiC LGADs. Without these numbers it is not possible to confirm that the observed signals arise from preserved LGAD avalanche operation rather than ordinary drift collection under the modified field geometry introduced by the trenches or gaps.
minor comments (1)
  1. [Abstract] The abstract states that devices were produced 'using multiple inter-channel isolation strategies' but does not indicate which strategy was used for the specific TPA-TCT data shown.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the careful and constructive review of our manuscript on the development of segmented 4H-SiC LGADs. We address the major comment below and have prepared revisions to strengthen the quantitative support for our claims.

read point-by-point responses

  1. Referee: [Abstract / TPA-TCT results] Abstract and Results section on TPA-TCT: the demonstration of 'clear charge separation ... with internal gain' is presented only qualitatively. No extracted values are given for inter-strip crosstalk (e.g., ratio of induced charge on the adjacent channel when the laser is focused on one strip) or for the multiplication factor relative to the preceding single-pad 4H-SiC LGADs. Without these numbers it is not possible to confirm that the observed signals arise from preserved LGAD avalanche operation rather than ordinary drift collection under the modified field geometry introduced by the trenches or gaps.

    Authors: We agree that the current presentation relies primarily on qualitative description and visual evidence from the TPA-TCT scans. To address this concern directly, the revised manuscript will include extracted quantitative metrics. We will report the inter-strip crosstalk as the ratio of integrated charge induced on the adjacent channel to the primary channel when the laser spot is centered on one strip. We will also extract the multiplication factor by comparing the observed charge collection to the expected ionization signal in 4H-SiC (accounting for the known pair-creation energy) and by direct comparison to the gain values measured on our preceding single-pad 4H-SiC LGAD devices. These numbers will be added to the Results section together with a brief discussion confirming that the avalanche gain mechanism remains operative after segmentation. revision: yes

Circularity Check

0 steps flagged

No significant circularity: pure experimental fabrication and measurement work

full rationale

The manuscript reports design, fabrication, and TPA-TCT characterization of the first segmented 4H-SiC LGAD strip and pixel devices. The central claim rests on direct experimental observation of charge separation between adjacent channels together with internal gain. No equations, fitted parameters, or predictions are presented that reduce by construction to prior inputs or self-citations. Prior single-pad prototypes are referenced only as background; the new segmentation results are independently measured and do not rely on any uniqueness theorem, ansatz, or renaming of known patterns from the authors' earlier work.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

This is an experimental device paper. The claim rests on standard semiconductor fabrication assumptions and the validity of TPA-TCT as a characterization method; no free parameters, ad-hoc axioms, or invented entities are introduced beyond established LGAD and SiC physics.

axioms (1)
  • domain assumption Standard semiconductor physics governing avalanche multiplication and charge transport in 4H-SiC applies without modification.
    Invoked implicitly when claiming internal gain from the LGAD structure.

pith-pipeline@v0.9.0 · 5802 in / 1169 out tokens · 41484 ms · 2026-05-20T13:42:31.874210+00:00 · methodology

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Reference graph

Works this paper leans on

19 extracted references · 19 canonical work pages

  1. [1]

    M.Levinshtein, S.RumyantsevandM.Shur,PropertiesofAdvancedSemiconductorMaterials: GaN, AlN, InN, BN, SiC, SiGe, Wiley (2001)

    work page 2001

  2. [2]

    A.Gsponer,S.Onder, S.Gundacker,J.Burin, M.Knopf,D.Radmanovacetal.,Extractionofelectron and hole drift velocities in thin 4h-sic pin detectors using high-frequency readout electronics,Sensors 25(2025) 7196

    work page 2025

  3. [3]

    J.M. Rafi, G. Pellegrini, P. Godignon, S.O. Ugobono, G. Rius, I. Tsunoda et al.,Electron, neutron, and proton irradiation effects on sic radiation detectors,IEEE Transactions on Nuclear Science67 (2020) 2481

    work page 2020

  4. [4]

    Moscatelli, A

    F. Moscatelli, A. Scorzoni, A. Poggi, M. Bruzzi, S. Sciortino, S. Lagomarsino et al.,Radiation hardness of minimum ionizing particle detectors based on sic p/sup +/n junctions, inIEEE Nuclear Science Symposium Conference Record, 2005, vol. 1, pp. 490–494, IEEE, 2005, DOI

    work page 2005

  5. [5]

    R. Wei, S. Song, K. Yang, Y. Cui, Y. Peng, X. Chen et al.,Thermal conductivity of 4h-sic single crystals,Journal of Applied Physics113(2013)

    work page 2013

  6. [6]

    Christanell, M

    M. Christanell, M. Tomaschek and T. Bergauer,4h-silicon carbide as particle detector for high-intensity ion beams,Journal of Instrumentation17(2022) C01060

    work page 2022

  7. [7]

    Pellegrini, P

    G. Pellegrini, P. Fernández-Martínez, M. Baselga, C. Fleta, D. Flores, V. Greco et al.,Technology developments and first measurements of low gain avalanche detectors (lgad) for high energy physics applications,Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment765(2014) 12

    work page 2014

  8. [8]

    ATLAS Collaboration,Technical design report: A high-granularity timing detector for the atlas phase-ii upgrade, Tech. Rep. CERN-LHCC-2020-007, ATLAS-TDR-031, CERN (2020)

    work page 2020

  9. [9]

    Paternoster, G

    G. Paternoster, G. Borghi, M. Boscardin, N. Cartiglia, M. Ferrero, F. Ficorella et al.,Novel strategies for fine-segmented low gain avalanche diodes,Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment987(2021) 164840

    work page 2021

  10. [10]

    Novotný, J

    R. Novotný, J. Chochol, V. Kafka, A. Klimsza, A. Kozelsky, J. Kroll et al.,First generation 4h-sic lgad production and its performance evaluation,Journal of Instrumentation20(2025) C08022. – 14 –

    work page 2025

  11. [11]

    Švihra, J

    P. Švihra, J. Chochol, V. Kafka, A. Klimsza, A. Kozelsky, J. Kroll et al.,Exploring the design and measurements of next-generation 4h-sic lgads,Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment1080(2025) 170742

    work page 2025

  12. [12]

    S. Zhao, K. Wang, K. Xie, C. Fu, C. Wang, S. Xiao et al.,Electrical properties and gain performance of 4h-sic lgad (sicar),IEEE Transactions on Nuclear Science71(2024) 2417

    work page 2024

  13. [13]

    T. Yang, B. Sekely, Y. Satapathy, G. Allion, P. Barletta, C. Haber et al.,Characterization of 4h-sic low gain avalanche detectors (lgads),Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment1082(2026) 170873

    work page 2026

  14. [14]

    Zat’ko, A

    B. Zat’ko, A. Šagátová, N. Gál, A. Novák, J. Osvald, P. Boháček et al.,From a single silicon carbide detector to pixelated structure for radiation imaging camera,Journal of Instrumentation17(2022) C12005

    work page 2022

  15. [15]

    Yang, B.J

    T. Yang, B.J. Sekely, Y. Satapathy, G. Allion, G. Atar, P. Barletta et al.,Ultra-fast 4h-sic lgad with etched termination and field plate,IEEE Electron Device Letters46(2025) 845

    work page 2025

  16. [16]

    Onder, P

    S. Onder, P. Gaggl, J. Burin, A. Gsponer, M. Knopf, S. Waid et al.,Design and simulation of a 4h-sic lowgainavalanchediodewithtrench-isolation,NuclearInstrumentsandMethodsinPhysicsResearch Section A: Accelerators, Spectrometers, Detectors and Associated Equipment1080(2025) 170740

    work page 2025

  17. [17]

    Marco-Hernández and ALIBAVA Collaboration,A portable readout system for microstrip silicon sensors (ALIBAVA),IEEE Transactions on Nuclear Science56(2009) 1642

    R. Marco-Hernández and ALIBAVA Collaboration,A portable readout system for microstrip silicon sensors (ALIBAVA),IEEE Transactions on Nuclear Science56(2009) 1642

    work page 2009

  18. [18]

    Llopart, J

    X. Llopart, J. Alozy, R. Ballabriga, M. Campbell, R. Casanova, V. Gromov et al.,Timepix4, a large area pixel detector readout chip which can be tiled on 4 sides providing sub-200 ps timestamp binning,Journal of Instrumentation17(2022) C01044

    work page 2022

  19. [19]

    Wiehe, M.F

    M. Wiehe, M.F. García, M. Moll, R. Montero, F.R. Palomo, I. Vila et al.,Development of a tabletop setup for the transient current technique using two-photon absorption in silicon particle detectors, IEEE Transactions on Nuclear Science68(2021) 220. – 15 –

    work page 2021