arXiv subjects

I. Zatocilova

Publications and source records attributed to I. Zatocilova.

3 recordsLinked to original sources

arXiv2026

The study of gamma-radiation induced displacement damage in $n^+$-in-$p$ silicon diodes

The bulk damage of $p$-type silicon sensors caused by gamma irradiation with high total ionizing doses has been investigated. The study was carried out on different types of $n^+$-in-$p$ silicon diodes with different oxygen concentrations and silicon bulk resistivities. The Secondary-Ion Mass Spectrometry technique was used to determine the relative concentration of oxygen in the individual samples. The measured diodes were irradiated by a $^{60}$Co gamma source to total ionizing doses ranging from 0.50 up to 8.28 MGy, and annealed for 80 minutes at 60°C. The main goal of the study was to characterize the gamma-radiation induced displacement damage by measuring IV and CV characteristics, and the evolution of the full depletion voltage with the total ionizing dose. The Transient Current Technique was used to verify the full depletion voltage and to extract the electric field distribution and the sign of the space charge in the silicon diodes irradiated to the lowest and the highest delivered total ionizing doses. The results show a linear increase of the bulk leakage current with the total ionizing dose, with the damage coefficient being dependent on initial resistivity and oxygen concentration of the silicon diode. The effective doping concentration and full depletion voltage decrease significantly with an increasing total ionizing dose, before starting to increase again at a specific dose. We assume that the initial decrease in the effective doping concentration is caused by the effect of acceptor removal. An additional notable finding of this study is that the bulk leakage current and CV characteristics of the gamma-irradiated diodes do not show any evidence of an annealing effect.

hep-ex↗

arXiv2023

Characterization, Simulation and Test Beam Data Analysis of Stitched Passive CMOS Strip Sensors

In the passive CMOS Strips Project, strip sensors were designed at the University of Bonn and produced by LFoundry in 150 nm technology, with an additional backside processing from IZM Berlin. Up to five individual reticules were connected by stitching at the foundry in order to obtain the typical strip lengths required for the LHC Phase-II upgrade of ATLAS or CMS trackers. After dicing, sensors were tested in a probe station and characterised with a Sr90-source as well as laser-based edge- and top-TCT systems. Sensors were also simulated using Sentaurus TCAD. At last, detector modules were constructed from several sensors and thoroughly studied in two beam campaigns at DESY. All of these measurements were performed before and after irradiation. This contribution provides an overview of simulation results, summarises the laboratory measurements and in particular presents first test beam results for irradiated and unirradiated passive CMOS strip sensors. We are demonstrating that large area sensors with sufficient radiation hardness can be obtained by stitching during the CMOS process, and presenting our plans for the next submission in the framework of this project.

physics.ins-det↗

arXiv2023

Study of Bulk Damage of High Dose Gamma Irradiated p-type Silicon Diodes with Various Resistivities

The bulk damage of p-type silicon detectors caused by high doses of gamma irradiation has been studied. The study was carried out on three types of n$^{+}$-in-p silicon diodes with comparable geometries but different initial resistivities. This allowed to determine how different initial parameters of studied samples influence radiation-induced changes in the measured characteristics. The diodes were irradiated by a Cobalt-60 gamma source to total ionizing doses ranging from 0.50 up to 8.28 MGy, and annealed for 80 minutes at 60 °C. The Geant4 toolkit for simulation of the passage of particles through matter was used to simulate the deposited energy homogeneity, to verify the equal distribution of total deposited energies through all the layers of irradiated samples, and to calculate the secondary electron spectra in the irradiation box. The main goal of the study was to characterize the gamma-radiation induced displacement damage by measuring current-voltage characteristics (IV), and the evolution of the full depletion voltage with the total ionizing dose, by measuring capacitance-voltage characteristics (CV). It has been observed that the bulk leakage current increases linearly with total ionizing dose, and the damage coefficient depends on the initial resistivity of the silicon diode. The effective doping concentration and therefore full depletion voltage significantly decreases with increasing total ionizing dose, before starting to increase again at a specific dose. We assume that this decrease is caused by the effect of acceptor removal. Another noteworthy observation of this study is that the IV and CV measurements of the gamma irradiated diodes do not reveal any annealing effect.

physics.ins-det↗