arXiv subjects

Ben J. Sekely

Publications and source records attributed to Ben J. Sekely.

3 recordsLinked to original sources

arXiv2026

Impact of Gain Layer Doping Concentration on the Performance of 4H-SiC LGADs

Gain layer doping concentration determines the electric field profile in a low gain avalanche detector (LGAD) and is therefore the primary design parameter. This work reports its influence on the charge collection and timing behavior of 4H-SiC LGADs. Two mesa-isolated devices with cold He ion implanted termination differ only in gain layer doping, $4\times10^{17}$~$cm^{-3}$ and $5\times10^{17}$~$cm^{-3}$, and are characterized together with a PIN diode from the same wafer using the ultraviolet transient current technique (UV-TCT). The 25\% doping difference produces a gain difference of about two orders of magnitude at the same applied bias, representing a gain range of 3.7 to 216. Under UV-TCT excitation, the higher-doped device exhibits time-resolution minima within a gain range of about 20--80 across the investigated laser intensities, consistent with the transition from electronic-noise-dominated jitter to multiplication shot noise. The non-monotonic timing response is also observed under a $^{90}Sr$ beta source with a Si LGAD reference: the higher-doped device reaches 51.7 ps at 280 V and then degrades, while the lower-doped device requires more than 450 V. This measured gain window provides an experimental reference for further optimization of the gain-layer design.

physics.ins-det↗

arXiv2025

Time Resolution Characterization of 4H-SiC LGADs with a ${}^{90}$Sr Source

This work presents timing measurements of 4H-SiC Low Gain Avalanche Detectors (4H-SiC LGADs) using beta particles from a ${}^{90}$Sr source. The 4H-SiC LGADs exhibit fast signal responses, and a time resolution of 61~ps was achieved, comparable to that of standard Si LGADs. The present limitation in the time resolution of 4H-SiC LGADs appears to stem from limited charge generation. Nevertheless, their higher voltage tolerance and faster carrier drift suggest that, with increased charge collection, their timing performance could approach or even surpass that of Si LGADs. These results demonstrate the strong potential of 4H-SiC LGADs as a robust platform for precision timing in future 4D tracking detectors, while also highlighting that signal charge is the dominant factor currently limiting their performance, indicating that further optimization of gain and drift structures will be essential for future development.

physics.ins-det↗

arXiv2025

Impact of Proton Irradiation on 4H-SiC Low Gain Avalanche Detectors (LGADs)

Silicon carbide (SiC) particle detectors have the potential to provide time resolutions and robust performance in extreme environments which exceed that of silicon detectors. In this work 4H-SiC low gain avalanche detectors (LGADs) and complementary PiN diodes were irradiated with 2.5 GeV protons at fluences up to 3.33$\times$10$^{14}$ p/cm$^2$. The electrostatic performance of both irradiated and non-irradiated devices was evaluated using current-voltage (I-V) and capacitance-voltage (C-V) measurements. Moreover, charge collection measurements using $α$ particles were also conducted. SiC LGADs displayed a loss in rectification and gain with increasing proton fluence. Additionally, the reduction in capacitance and OFF-state current pointed to compensation of the gain layer as a gain reducing mechanism. The introduction of radiation induced defects also hinders carrier acceleration reducing impact ionization, leading to further gain reduction. However, despite the reduction in device performance, the demonstration of a measurable signal and gain after irradiation points to the potential of SiC LGAD detectors for future high energy physics applications.

physics.ins-det↗