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Depletion depth measurements of new large area silicon carbide detectors

A. Spatafora, D. Carbone, L. La Fauci, G. A. Brischetto, D. Calvo, F. Cappuzzello, M. Cavallaro, A. Crnjac, K. Ivanković Nizić, M. Jakšić, D. Torresi, S. Tudisco

TL;DR

This work assesses depletion depth and energy-loss accuracy in new large-area SiC detectors intended for particle identification in NUMEN/MAGNEX. Using ion-beam induced charge (IBIC) with a proton microbeam, the authors validate Ziegler energy-loss tables and extract a global normalization factor $K ≈ 0.965$ for 6.00 MeV protons, enabling accurate depletion-depth measurements. Two wafers with different doping are studied: TT0012-11 yields a depletion depth near 100 μm, while RA0089-27 shows ≈94 μm, confirming the crucial role of epitaxial doping on full depletion. The results support the feasibility of large-area SiC detectors for NUMEN while highlighting the need for improved low-doping epitaxy to achieve uniform performance across devices.

Abstract

The ion beam induced charge technique with proton microprobe is used to characterise newly developed p-n junction large area silicon carbide detectors. They were recently produced as part of the ongoing program to develop a new particle identification wall for the focal plane detector of the MAGNEX magnetic spectrometer at INFN - Laboratori Nazionali del Sud in view of the NUMEN experimental campaigns. Four silicon carbide devices are studied. Proton beams over a 1.26 to 6.00 MeV incident energy range are used to probe the active area and the depletion depth of each device. The energy loss tables for the silicon carbide material are checked, finding an empirical correction that is then used to quantify the depletion depth at the full depletion voltage through energy loss measurements of 3.40 MeV proton beams irradiating the back side of the devices. It is possible to fully deplete the devices provided that the epitaxial layer is grown properly on the substrate.

Depletion depth measurements of new large area silicon carbide detectors

TL;DR

This work assesses depletion depth and energy-loss accuracy in new large-area SiC detectors intended for particle identification in NUMEN/MAGNEX. Using ion-beam induced charge (IBIC) with a proton microbeam, the authors validate Ziegler energy-loss tables and extract a global normalization factor for 6.00 MeV protons, enabling accurate depletion-depth measurements. Two wafers with different doping are studied: TT0012-11 yields a depletion depth near 100 μm, while RA0089-27 shows ≈94 μm, confirming the crucial role of epitaxial doping on full depletion. The results support the feasibility of large-area SiC detectors for NUMEN while highlighting the need for improved low-doping epitaxy to achieve uniform performance across devices.

Abstract

The ion beam induced charge technique with proton microprobe is used to characterise newly developed p-n junction large area silicon carbide detectors. They were recently produced as part of the ongoing program to develop a new particle identification wall for the focal plane detector of the MAGNEX magnetic spectrometer at INFN - Laboratori Nazionali del Sud in view of the NUMEN experimental campaigns. Four silicon carbide devices are studied. Proton beams over a 1.26 to 6.00 MeV incident energy range are used to probe the active area and the depletion depth of each device. The energy loss tables for the silicon carbide material are checked, finding an empirical correction that is then used to quantify the depletion depth at the full depletion voltage through energy loss measurements of 3.40 MeV proton beams irradiating the back side of the devices. It is possible to fully deplete the devices provided that the epitaxial layer is grown properly on the substrate.
Paper Structure (7 sections, 3 equations, 3 figures, 2 tables)

This paper contains 7 sections, 3 equations, 3 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Large area Silicon Carbide detectors
  3. Experimental setup
  4. Validation of the energy loss tables of Ziegler
  5. Measurement of the depletion depth
  6. Conclusions
  7. Acknowledgements

Figures (3)

  • Figure 1: Views of the TT0012-11 A41 SiC device. a) Sketch of the sectional view illustrating the active area structure of the SiC device (not to scale). b) Picture of the device mounted on the PCB board inside the scattering chamber.
  • Figure 2: Ionization profile for 6.00 MeV proton energy, impinging at $\theta$ = 0$^\circ$, as obtained from simulations performed with the SRIM software SRIM2010 using the Ziegler energy loss tables Ziegler1985. Different materials are considered corresponding to the different layers of the SiC and the PIPS detectors: Al (red band), SiC (gray band for the active region and green hatched band for the dead layer), Ni$_2$Si (yellow band), Si (blue band). The vacuum area of $\approx$ 5 cm between SiC and PIPS is indicated as the white band.
  • Figure 3: Scheme of the experimental setup for the 3.40 MeV proton irradiation from the SiC back side at different angles. The SiC active region and the dead layer are indicated as the gray and green hatched bands, respectively.