arXiv subjects

Jürgen Burin

Publications and source records attributed to Jürgen Burin.

9 recordsLinked to original sources

arXiv2025

TCAD Parameters for 4H-SiC: A Review

In this literature review we investigate the permittivity, density-of-state mass, band gap, impact ionization, charge carrier recombination, incomplete ionization and mobility in 4H silicon carbide. We provide a comprehensive overview over characterization methods, models and parameters to lower the entrance barrier for newcomers and allow a critical evaluation of common material property descriptions. We further highlight areas for future research by identifying gaps in the current knowledge base. For each investigated property we found a large amount of models and parameter sets based on measurements, calculations or fittings. With literal and/or graphical comparisons we reveal qualitative good agreement but also flawed data values, misinterpretations of research results and inconsistencies among multiple investigations, even those directly referencing each other. We identify parameter variations, e.g., due to temperature, with high impact that are rarely considered in 4H-SiC analyses and common values that are based on old research of deviating materials or properties. We further show the slow accommodation of recent research results within the scientific community and reveal missing characterization data but also insufficient models in state-of-the-art technology computer aided design (TCAD) tools. Overall, our review enables scientifically based decisions on 4H-SiC material parameters and unravels the demand for further investigations to validate commonly used values, confirm hypothesis and cover additional dependencies.

cond-mat.mtrl-sci↗

arXiv2025

Design and simulation of a 4H-SiC low gain avalanche diode with trench-isolation

We present the design and simulation of a 30 $\mathrm{μm}$ thick 4H-SiC Low Gain Avalanche Diode (LGAD) optimized for high-voltage operation. A 2.4 $\mathrm{μm}$ thick epitaxially grown gain layer enables controlled internal amplification up to 1 kV reverse bias, while maintaining full depletion below 500 V. Electrical characteristics, including I-V, C-V, and gain behavior, were simulated in Synopsys Sentaurus Technology Computer-Aided Design (TCAD) using a quasi-1D geometry and verified across process-related variations in gain layer parameters. To ensure high-voltage stability and proper edge termination, a guard structure combining deep etched trenches and deep $p^+$ junction termination extension (JTE) implants was designed. TCAD simulations varying the guard structure dimensions yielded an optimized design with a breakdown voltage above 2.4 kV. A corresponding wafer run is currently processed at IMB-CNM, Barcelona.

physics.ins-det↗

arXiv2025

Extraction of Electron and Hole Drift Velocities in thin 4H-SiC PIN Detectors using High-Frequency Readout Electronics

Silicon carbide (SiC) has been widely adopted in the semiconductor industry, particularly in power electronics, because of its high temperature stability, high breakdown field, and fast switching speeds. Its wide band gap makes it an interesting candidate for radiation-hard particle detectors in high-energy physics and medical applications. Furthermore, the high electron and hole drift velocities in 4H-SiC enable devices suitable for ultra-fast particle detection and timing applications. However, currently, the front-end readout electronics used for 4H-SiC detectors constitute a bottleneck in investigations of the charge carrier drift. To address these limitations, a high-frequency readout board with an intrinsic bandwidth of 10 GHz was developed. With this readout, the transient current signals of a 4H-SiC diode with a diameter of 141 $\mathrm{μm}$ and a thickness of 50 $\mathrm{μm}$ upon UV-laser, alpha particle, and high-energy proton beam excitation were recorded. In all three cases, the electron and hole drift can clearly be separated, which enables the extraction of the charge carrier drift velocities as a function of the electric field. These velocities, for the first time directly measured, provide a valuable comparison to Monte-Carlo simulated literature values and constitute an essential input for TCAD simulations. Finally, a complete simulation environment combining TCAD, the Allpix$^2$ framework, and SPICE simulations is presented, in good agreement with the measured data.

physics.ins-det↗

arXiv2025

From Single Particles to Clinical Beam Rates: A Wide Dynamic Range Beam Monitor

Access to high-energy particle beams is key for testing high-energy physics (HEP) instruments. Accelerators for cancer treatment can serve as such a testing ground. However, HEP instrument tests typically require particle fluxes significantly lower than for cancer treatment. Thus, facilities need adaptations to fulfill both the requirements for cancer treatment and the requirements for HEP instrument testing. We report on the progress made in developing a beam monitor with a sufficient dynamic range to allow for the detection of single particles, while still being able to act as a monitor at the clinical particle rates of the MedAustron treatment facility. The beam monitor is designed for integration into existing accelerators.

physics.acc-ph↗

arXiv2024

Observation of Charge Enhancement in forward-biased neutron-irradiated 4H-SiC PiN Detectors in UV-TCT Measurements

Due to the increased commercial availability, wide-bandgap semiconductors and their radiation hardness have recently received increased interest from the particle physics community. 4H-Silicon Carbide (SiC), especially, is an attractive candidate for future radiation-hard detectors which do not require cooling. This paper investigates the radiation hardness of 4H-SiC p-in-n detectors irradiated up to $5\times 10^{15}$ $\text{n}_{\text{eq.}}/\text{cm}^2$ using UV-TCT. The samples have been operated in reverse and forward bias, which is possible due to the heavily decreased forward current after irradiation. Previous studies have already hinted at an excessive charge collection in forward bias, even exceeding a charge collection efficiency (CCE) of 100%. In this work, the excessive CCE in forward bias was shown to correlate heavily with the spatial profile of injected charge. For a sufficiently focused laser, the CCE starts to increase at high forward bias and even surpasses 100% instead of saturating as it does for a defocused laser beam. In reverse bias, the CCE was found to be independent of the beam spot size. For samples irradiated to high fluences ($\geq 1\times 10^{15}$ $\text{n}_{\text{eq.}}/\text{cm}^2$) the excessive CCE in forward bias is smaller and negligible at the highest fluences. Additionally, the CCE was observed to correlate to the rate of charge injection (laser pulses per second), with a logarithmic increase of the collected charge if a threshold of injected carrier density is exceeded. The mechanism of these effects is still an ongoing topic of study, however, the observations already pose implications for the accurate experimental characterization of irradiated SiC detectors.

physics.ins-det↗

arXiv2024

TCAD modeling of radiation-induced defects in 4H-SiC diodes

Silicon Carbide (SiC) has several advantageous properties compared to Silicon (Si) that make it an appealing detector material, such as a larger charge carrier saturation velocity, bandgap, and thermal conductivity. While the current understanding of material and model parameters suffices to simulate unirradiated 4H-SiC devices using technical computer-aided design (TCAD), configurations to accurately predict performance degradation after high levels of irradiation due to induced defects acting as traps and recombination centers do not exist. Despite increasing efforts to characterize the introduction and nature of such defects in 4H-SiC, published results are often contradictory. This work presents a bulk radiation damage model for TCAD simulations based on measurements on 50 $μm$ 4H-SiC pad diodes, neutron-irradiated at various fluxes ranging from $5\times 10^{14}$ $n_{eq}/cm^2$ to $1\times 10^{16}$ $n_{eq}/cm^2$. The model accurately predicts internal electric shifts, such as flattening of the detector capacitance, degradation in charge collection efficiency (CCE), and signal detection capabilities under forward bias conditions up to high bias. It further introduces the EH$_4$ defect cluster as major lifetime killer and reinforces the assumption of the EH$_{6,7}$ deep-level defect to be of donor type.

physics.ins-det↗

arXiv2024

TCAD Simulations of Radiation Damage in 4H-SiC

To increase the scientific output of particle physics experiments, upgrades are underway at all major accelerator facilities to significantly improve the luminosity. Consequently, the solid-state detectors used in the experiments will exhibit more severe radiation-induced damage. To ensure sufficiently long sensor lifetimes, alternative materials to the established silicon sensors, with improved resilience to radiation, are investigated. For one of the promising candidate materials, silicon carbide, only recently a model describing the radiation damage in technology aided computer design (TCAD) simulations has been proposed. In this paper we present our latest achievements towards modeling radiation damage of 4H-SiC in TCAD tools. We first verify the utilized TCAD framework against published silicon data and then use it to approximate measurements of neutron-irradiated 4H-SiC particle detectors. We are able to confirm in simulations the measurement results, i.e., an almost flat capacitance as a function of bias voltage and a decreasing forward current with increasing particle fluence. Based on our simulations we are able to explain the latter by trapped charge carriers that create a space charge region within the device.

physics.ins-det↗

arXiv2024

Measurement of the electron-hole pair creation energy in a 4H-SiC p-n diode

For 4H silicon carbide (4H-SiC), the values for the electron-hole pair creation energy $ε_{\text{i}}$ published in the literature vary significantly. This work presents an experimental determination of $ε_{\text{i}}$ using $50$ $μ$m 4H-SiC p-n diodes designed for particle detection in high-energy physics. The detector response was measured for $α$ particles between 4.2 MeV and 5.6 MeV for 4H-SiC and a silicon reference device. Different $α$ energies were obtained by using multiple nuclides and varying the effective air gap between the $α$ source and the detector. The energy deposited in the detectors was determined using a Monte Carlo simulation, taking into account the device cross-sections. A linear fit of the detector response to the deposited energy yields $ε_{\text{i}} = (7.83 \pm 0.02)\;\text{eV}$, which agrees well with the most recent literature. For the 4H-SiC detectors, a linewidth of 28 keV FWHM was achieved, corresponding to an energy resolution of 0.5\%.

physics.ins-det↗

arXiv2024

Pulsed RF Knock-Out Extraction: A Potential Enabler for FLASH Hadrontherapy in the Bragg Peak

One challenge on the path to delivering FLASH-compatible beams with a synchrotron is facilitating an accurate dose-control for the required ultra-high dose rates. We propose the use of pulsed RFKO extraction instead of continuous beam delivery as a way to control the dose delivered per Voxel. In a first feasibility test dose rates in pulses of up to 600 Gy/s were observed, while the granularity at which the dose was delivered is expected to be well below 0.5 Gy.

physics.med-ph↗