International Round-Robin Tests on Solar Cell Degradation Due to Electrostatic Discharge

Primary discharge occurs on solar arrays due to their interaction with the space plasma. A solar cell may suffer degradation of electrical performance if the primary discharge occurs at the cell edge. To estimate the power generated at the end of life, it is necessary to study the details of solar cell degradation. However, throughout the world, primary discharge has not been recognized as a cause of solar cell degradation. There is now an international collaboration among institutions in Japan, France, and the United States toward a common international standardization of solar array electrostatic discharge test methods. Round-robin tests were carried out as part of this collaborative research. Laboratory experiments were performed at the same time in three institutions using the same test method and identical solar cells. Solar cell degradation was confirmed at all three institutions. It was found that a multijunction solar cell is more susceptible to damage from primary discharge than a crystalline silicon solar cell. Throughout the round-robin tests, discharge has been shown to be a significant cause of solar cell degradation

SEU rate calculation with GEANT4 (comparison with CREME 86)

This paper reports on single-event upset (SEU) rate calculations using the GEANT4 code. Single event effect rate modeling can be performed using various approaches. In this paper, we propose to compare the standard rectangular parallepiped (RPP) cosmic ray effects in microelectronic code (CREME86) model with our direct Monte Carlo simulation using the GEANT 4 (radiation transport code developed by CERN) software. The results obtained on two device types are in good agreement with CREME86. (14 refs)

Physical Mechanisms of Proton-Induced Single-Event Upset in Integrated Memory Devices

International audienceThe sensitivity of memory devices under proton irradiation has been extensively studied over the years. Two main mechanisms have been identified to drive the single-event upset (SEU) sensitivity in the last generation of devices: direct ionization for low proton energies and inelastic nuclear reactions for higher proton energies. Some papers have shown that the Coulomb elastic contribution should be considered. This paper supports this conclusion and proposes analyses in order to show the importance of this contribution according to the technological node studied

Monte Carlo Simulations of Low Energy Electrons in Silicon

International audienceThe electron transport in silicon at low and very low energy (10 eV-2 keV) is investigated with a Monte Carlo code. The elastic scattering with nuclei is described by Mott's model of partial waves, whereas the inelastic collisions with electrons are described by the complex dielectric function theory. The code has been validated by means of comparison with electron emission yields (EEY) and energy loss spectra experimentally measured in ultrahigh vacuum on an Ar-etched sample. Electron emission yields, practical ranges, and ionizing doses are presented for electrons in silicon down to 10 eV

Electron emission yield for low energy electrons: Monte Carlo simulation and experimental comparison for Al, Ag, and Si

International audienceThe electron emission under electron impact between 10 eV and 2 keV is investigated with a Monte Carlo (MC) code in aluminum, silver, and silicon. The code is based on the complex dielectric function theory to describe the inelastic scattering and uses the Mott's model of partial waves to describe the elastic scattering. It takes into account both volume and surface plasmon excitations. The simulation results are compared with the experimental measurements of electron emission yields (EEY) and energy spectra of low energy electrons performed in ultrahigh vacuum on Ar-etched bulk samples. Our MC simulations at low energy are found to be in fairly good agreement with our experimental measurements. The peaks corresponding to the surface plasmon, the volume plasmon and its multiples and to the Auger transitions appear clearly on the energy loss spectra of aluminum, silver, and silicon. The simulated EEY are also in fairly good agreement with our measurements and with data from the literature. The EEY at normal incidence is studied for secondary and backscattered electrons. A focus is made for the EEY below 50 eV where a fairly good agreement is found with Bronstein and Fraiman's measurements on vacuum evaporated samples. Below 2 keV, for silver and aluminum, the total EEY is given for different angles of incidence θ. Some discrepancies are observed between our experimental measurements and our MC simulations for high angles of incidence. These discrepancies can be attributed to the modeling of surface plasmon excitations, surface oxidation, or roughness that occur during the Ar-etching process

Measurements of radiation induced defects in quartz material by Dielectric Relaxation Spectroscopy

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Using a carbon beam as a probe to extract the thickness of sensitive volumes

The upset rate calculation depends on the energy deposited along the secondaries paths in a sensitive volume (Sv) of thickness d. We have developed a new extraction method in order to get d from experimental data. It is based upon the deconvolution of the heavy ion upset cross section function sigma(seu)(r) with LET(r) (r is the range of the incident ion)

NIEL calculations for estimating the displacement damage introduced in GaAs irradiated with charged particles

International audienceThe application of Non-Ionizing Energy Loss (NIEL) in estimating the impact of electron, proton, and heavy ion irradiations on Gallium Arsenide is presented in this paper. The NIEL for deuteron, alpha particle, lithium ion and oxygen ion is computed using the SR-NIEL and NEMO codes. The NIEL calculations are compared with the introduction rate of displacement damage measured in n-type GaAs. Very good agreement is found between the NIEL and experimental results for protons (< 20 MeV), electrons, and a variety of ions. However, a discrepancy can be observed for high-energy protons