Abstract
We report on silicon carbide (SiC) p-n junction diodes with a high blocking voltage over 3 kV. Although SiC radiation sensors have been developed with a Schottky barrier type due to a simple fabrication process in the early stages, p-n junction structures are advantageous due to lower sensitivity of the surface defects. Thus, this system provides an ideal condition to investigate the effect of bulk crystal defects on the characteristics of the radiation sensor. The p-n diodes were designed with a device simulator and fabricated with a 4-in 4H-SiC wafer. The epitaxial layer was grown on an n-type substrate with sufficiently low doping concentration of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${N_{\mathrm{ d}}} - {N_{\mathrm{ a}}}=\sim 5\times 10^{14} {\mathrm{ cm}}^{-3}$ </tex-math></inline-formula> and an average thickness of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$52 ~\mu {\mathrm{ m}}$ </tex-math></inline-formula> . Fabricated p-n diodes with a relatively large leakage current still show a clear peak of the Landau distribution in the charge spectrum, suggesting their practical availability as minimum ionizing particle (MIP) detectors. The estimated electron–hole pair creation energy is consistent with the published studies and we expect good radiation tolerance. Feasibility based on the wafer processing indicates that the prototype devices are a good candidate for the muon beam monitor application in the COherent Muon-to-Electron Transition (COMET) experiment at Japan Proton Accelerator Research Complex (J-PARC).
Highlights
S ILICON carbide (SiC) has been considered as a potential alternative to Si for the manufacture of dosimeters, spectrometers, and charge particle detectors in high energy physics experiments, by virtue of its operation capability in strong radiation and/or high-temperature environments [1], [2]
The thin active layer especially imposes a severe constraint on usage as a minimum ionizing particle (MIP) detector, compared with silicon sensors in high energy physics (HEP) experiments
To take advantage of such properties for future radiation detectors with a comparable size of silicon, we firstly investigated the influence of the bulk defects on the radiation sensor characteristics, by minimizing the surface contribution to the leakage current with a relatively small scale pn junction structure
Summary
S ILICON carbide (SiC) has been considered as a potential alternative to Si for the manufacture of dosimeters, spectrometers, and charge particle detectors in high energy physics experiments, by virtue of its operation capability in strong radiation and/or high-temperature environments [1], [2]. The pn or p-i-n structures of SiC are expected to provide radiation sensors with low leakage current as the wide band gap semiconductor in general. This is due to the fact that it has lower surface sensitivity to the active region in wafer processing and/or the avalanche multiplication inside the device to supplements the low signal charges. To take advantage of such properties for future radiation detectors with a comparable size of silicon, we firstly investigated the influence of the bulk defects on the radiation sensor characteristics, by minimizing the surface contribution to the leakage current with a relatively small scale pn junction structure.
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