Search results for "radiation effect"

UV-Photoinduced Defects In Ge-Doped Optical Fibers

2005

We investigated the effect of continuous-wave (cw) UV laser radiation on single-mode Ge-doped H2- loaded optical fibers. An innovative technique was developed to measure the optical absorption (OA) induced in the samples by irradiation, and to study its dependence from laser fluence. The combined use of the electron spin resonance (ESR) technique allowed the structural identification of several radiation-induced point defects, among which the Ge(1) (GeO4 -) is found to be responsible of induced OA in the investigated spectral region.

Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs

2019

GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (R) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (R) characteristic…

Radiation Hardened Optical Frequency Domain Reflectometry Distributed Temperature Fiber-Based Sensors

2015

International audience; We study the performance of Optical Frequency Domain Reflectometry (OFDR) distributed temperature sensors using radiation resistant single-mode optical fibers. In situ experiments under 10 keV X-rays exposure up to 1 MGy( SiO 2 ) were carried out with an original setup that allows to investigate combined temperature and radiation effects on the sensors within a temperature range from 30 ° C to 250 ° C. Obtained results demonstrate that optical fiber sensors based on Rayleigh technique are almost unaffected by radiation up to the explored doses. We show that a pre-thermal treatment stabilize the sensor performance increasing the accuracy on temperature measurement fro…

In-situ observation of beta-ray induced UV optical absorption in a-SiO2: radiation darkening and room temperature recovery

2006

International audience; We studied the optical absorption in the 3.0-6.2 eV range induced in bulk amorphous SiO2 by beta-ray irradiation up to similar to 1 MGy at room temperature. The induced absorption was measured in situ both during irradiation and in the post irradiation time. Our data evidence E', center as the main defect induced by irradiation and the partial decay of their absorption band at about 5.8 eV after irradiation. A quantitative analysis of the time evolution of the induced absorption shows that the transmission recovery observed after irradiation is compatible with the reaction of radiation-induced defects with H-related (H-2, H2O) species diffusing in the amorphous matrix

Influence of specific codopants and post-treatments on Erbium Doped Fibers: Radiation behavior characteristics by CML

2010

Proton irradiation-induced reliability degradation of SiC power MOSFET

2023

The effect of 53 MeV proton irradiation on the reliability of silicon carbide power MOSFETs was investigated. Post-irradiation gate voltage stress was applied and early failures in time-dependent dielectric breakdown (TDDB) test were observed for irradiated devices. The applied drain voltage during irradiation affects the degradation probability observed by TDDB tests. Proton-induced single event burnouts (SEB) were observed for devices which were biased close to their maximum rated voltage. The secondary particle production as a result of primary proton interaction with the device material was simulated with the Geant4-based toolkit. peerReviewed

Key Contributions to the Cross Section of NAND Flash Memories Irradiated With Heavy Ions

2008

Heavy-ion irradiation of NAND flash memories under operating conditions leads to errors with complex, data-dependent signatures. We present upsets due to hits in the floating gate array and in the peripheral circuitry, discussing their peculiarities in terms of pattern dependence and annealing. We also illustrate single event functional interruptions, which lead to errors during erase and program operations. To account for all the phenomena we observe during and after irradiation, we propose an ldquoeffective cross section,rdquo which takes into account the array and peripheral circuitry contributions to the SEU sensitivity, as well as the operating conditions.

Radiation-induced defects in fluorine-doped silica-based optical fibers: Influence of a pre-loading with H2

2009

International audience; We investigated the effects of 10-keV X-ray radiation on the transmission properties of F-doped optical fibers in the 200–850 nm range of wavelengths (1.5–6 eV). We also studied the influence of pre-loading this kind of fibers with hydrogen on its radiation sensitivity. Our results showed that, for our experimental conditions (pre-treatment with H2 several months before irradiation with diffusion of all the H2 out the fiber core and cladding before X-ray exposure), this pre-treatment increases the radiation-induced attenuation in the ultraviolet part (200–300 nm) of the spectrum. A previous H2-loading has no influence at greater wavelengths. The nature of the radiati…

Irradiation induced defects in fluorine doped silica

2008

International audience; The role of fluorine doping in the response to UV pulsed laser and c radiation of silica preforms and fibers was studied using electron spin resonance (ESR) spectroscopy. Exposure to radiation mainly generates E0 centers, with the same effectiveness in fibers and in preforms. The E'concentration in F-doped silica fibers is found to increase with UV energy fluence till a saturation value, consistently with a precursor conversion process. These results show the fluorine role in reducing the strained Si–O bonds thus improving the radiation hardness of silica, also after drawing process.

Bleaching of optical activity induced by UV Laser exposure in natural silica

2004

We report experimental data on two types of natural silica, differing for their OH content, irradiated with UV photons (4.66 eV) from a pulsed Nd:YAG laser. Irradiation induces a reduction of the absorption band at 5.12eV and of the associated emissions at 3.14eV and 4.28eV, ascribed to twofold coordinated Ge (=Ge'') centers pre-existing in our samples. The bleaching is mainly due to the post-irradiation conversion of =Ge'' into the paramagnetic H(II) center via trapping of a H atom. Comparison with literature data points out the peculiarities of silica with a low Ge concentration as regards UV induced transformations.