Speaker
Description
Silicon Carbide (SiC) detectors are gaining renewed research interest alongside the material's growing adoption in power electronics. The physical properties relevant to power electronics are also advantageous for detector applications, and SiC timing detectors could replace silicon detectors in the future. One limitation of SiC, however, is the currently limited epitaxial thickness that can be grown and depleted, which creates significant challenges for detecting and timing MIPs. This can be overcome by introducing charge multiplication, i.e., low-gain avalanche diodes (LGADs). SiC-LGADs are currently a topic of very high interest, as the performance of SiC-LGADs could surpass that of Si-LGADs.
We present the current status of SiC detector development at HEPHY and characterization of samples produced by CNM. The material properties of unirradiated 4H-SiC have been studied in an extensive literature review and by measurements using 50 and 100 µm thick detectors, for example, to determine the electron-hole pair ionization energy. In order to investigate the radiation hardness of 4H-SiC, two irradiation campaigns were conducted, reaching 1 MeV neutron equivalent fluences of $1 \cdot 10^{16}/$cm$^2$ and, recently, $1 \cdot 10^{18}/$cm$^2$. Above a fluence of $1 \cdot 10^{14}/$cm$^2$, the SiC epi-layer becomes intrinsic and can be operated in forward and reverse bias with negligible leakage currents. The charge collection efficiency has been investigated by alpha particles, protons, and UV-TCT and a TCAD radiation model has been built. In forward bias operation, charge enhancement (surpassing 100% charge collection efficiency) has been observed and is shown to correlate with the density of injected charge.
Furthermore, medical applications of SiC detectors at the MedAustron ion therapy facility are presented. SiC detectors have been used for ultra-high dose rate studies, providing crucial insights into the beam extraction profiles. Additionally, SiC microdosimeters and a SiC-based beam monitoring system are under development.
Finally, we present the design of our first SiC-LGAD run, which is currently being produced by CNM on 6-inch wafers. The expected performance of the SiC-LGADs, as well as the design challenges and tradeoffs, are discussed.
