1,720,982 research outputs found
Ionizing radiation induced leakage current on ultra-thin gate oxides
No full textMOS capacitors with a 4.4 nm thick gate oxide have been exposed to gamma radiation from a Co-60 source. As a result, we have measured a stable leakage current at fields lower than those required for Fowler-Nordheim tunneling. This Radiation Induced Leakage Current (RILC) is similar to the usual Stress Induced Leakage Currents (SILC) observed after electrical stresses of MOS devices. We have verified that these two currents share the same dependence on the oxide field, and the RILC contribution can be normalized to an equivalent injected charge for Constant Current Stresses. We have also considered the dependence of the RILC from the cumulative radiation dose, and from the applied bias during irradiation, suggesting a correlation between RILC and the distribution of trapped holes and neutral levels in the oxide layer
Radiation Effects On Ac-coupled Microstrip Silicon Detectors
No full textThe radiation hardness of FOXFET biased ac-coupled microstrip detectors, foreseen for the upgraded version of the vertex detectors (SVX') of the CDF experiment, has been studied. The detectors have been irradiated with Co-60 gamma rays with doses up to 1 Mrad. Two basic effects have been investigated: a variation of the switching voltage up to 100% due to oxide charge accumulation and Si/SiO2 interface trap formation, and a 12-fold increase of the total leakage current, likely to come from surface damage. Moreover, a 10-fold decrease of the FOXFET dynamic resistance is observed at low gate bias. Post-irradiation annealing effects at room temperature of the electrical detector parameters are currently under investigation, in particular on a single shot 1 Mrad irradiated device. Recovery phenomena toward the pre-irradiation values are observed only for the switching voltage due to the annealing of trapped oxide charge
PREPARATION AND CHARACTERIZATION OF Au/InGaP/GaAs SCHOTTKY BARRIERS FOR RADIATION DAMAGE INVESTIGATIONS
No full textAn Analysis of Complex Spectra from Deep Level Transient Capacitance Measurements
No full textThe effect of complex sets of single- and double-level traps on deep level transient spectroscopy (DLTS) spectra is critically discussed using a numerical simulator. The simulation takes into account: the partial trap ionization, the effect of base doping, the dynamics of charged traps, and the depletion layer effect. The modeling of the capacitance transient has been extended when many traps are present. The simulator has been used for the analysis of DLTS spectra of platinum-doped and high-energy (12 MeV) electron.irradiated silicon diodes. These examples evidence how the simulation method increases the resolution of the DLTS technique. A detailed analysis of the emission kynetics of the two energy level traps is also presented
Degradation of Silicon Ac-coupled Microstrip Detectors Induced By Radiation
No full textResults are presented showing the radiation response of ac-coupled FOXFET biased microstrip detectors and related test patterns to be used in the microvertex detector of the CDF experiment at Fermi National Laboratory. Radiation tolerance of detectors to gamma and proton irradiation has been tested and the radiation induced variations of the dc electrical parameters have been analyzed. Long term post-irradiation behaviour of detector characteristics have been studied, and the relevant room temperature annealing phenomena have been discussed
Forward and reverse characteristics of irradiated MOSFETs
No full textpMOSFETs biased with Vgs<Vgd during Co60 γ irradiation have shown substantial differences between the forward and reverse subthreshold characteristics, induced by a non-uniform charge distribution in the gate oxide. Correspondingly, modest differences have been observed in the over-threshold I-V characteristics. After irradiation, the forward subthreshold curves can shift at higher or lower gate voltages than the reverse ones. The former behaviour has been observed in long-channel devices, in agreement with the classical MOS theory and numerical simulations. The latter result has been obtained in short-channel devices, and it has been correlated to a parasitic punch-through conduction mechanism
Asymmetrical Oxide-Charge Build-up in Irradiated p-MOSFETs
No full textThe presence of an asymmetrical oxide-charge distribution in p-MOSFET`s irradiated under nonzero drain-to-source bias is pointed out by measuring the forward and reverse Id(Vgs) subthreshold characteristics. Numerical device simulation allow a better understanding of device operation to be achieved and provide an explanation for some aspects of the Id(Vgs) characteristics which can not be given on the basis of the experimental results only
Recombination Centers, Carrier Lifetime, and Electrical Characteristics in Electron Irradiated Power Semiconductor Devices
No full textRecombination Centers and Electrical Characteristics in Silicon P-i-N Diodes Irradiated with Energy Electrons
No full textBreakdown properties of irradiated MOS capacitors
No full textWe have studied the effects of ionizing and non-ionizing radiation on the breakdown properties of different types of MOS capacitors, with thick (200 nm) and thin (down to 8 nm) oxides. In general, no large variations of the average breakdown field, time-to-breakdown at constant voltage, or charge-to-breakdown values have been observed after high dose irradiation (20 Mrad(Si) 9 MeV electrons on thin and thick oxides, 17(Si) Mrad Co60 gamma and 1014 neutrons/cm2 only on thick oxides). However, Some modifications of the cumulative failure distributions have been observed in few of the oxides tested
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