Search

Heavy-ion-induced single-event transients (SET) are studied by device simulation on an ATMEL spatial component: the CMOS bulk 0.18 [micro]m inverter. The wide temperature range of a spatial environment (from 218 to 418 K) can modifiy the shape of the SET. Thus, an investigation of the SET propagation through a 10-inverter logic chain is performed in the 218-418 K temperature range, and the threshold LET (LETth) required for unattenuated propagation through the inverter chain is determined. The LETth is calculated for two different locations of the heavy ion impact and for three temperature values. An increase of the sensitivity is found when the temperature is raised from 218 to 418 K. Index Terms--CMOS, heavy ion, LET, single event transient (SET), technology computer-aided design (TCAD) simulation, temperature dependence.

A simulation tool to predict the heavy ion cross section is proposed. A 20% average error between experimental and simulated results is shown for a SRAM in a commercial 130 nm CMOS technology. Input parameters are obtained by device or circuit simulations and no fitting parameters or empirical calibration with previous radiation testings is needed. Index Terms--Cross section, heavy ion, passivation, PHISco, PMOS, SEU.

A temperature dependence analysis of single event transient currents induced by heavy-ions using TCAD simulation is performed in the 218 to 418 K range on a 0.18 [micro]m SRAM cell manufactured by ATMEL. The Single Event Upset (SEU) phenomena depends on both the heavy-ions-induced transient current and the technology. Temperature is shown to have a significant impact on the trends of heavy-ions-induced current. The SEU sensitivity is then expected to exhibit a large temperature dependence. However, a small influence on the SEU sensitivity is reported in this work on the studied technology. Index Terms--Heavy-ion, single event transient, single event upset sensitivity, SRAM, technology computer-aided design (TCAD) simulation, temperature dependence.

The possibility to evaluate simultaneously the total ionizing dose and the displacement damage dose using a single OSL integrated sensor is demonstrated. Results obtained during the real time monitoring of both proton and electron beams are presented. Index Terms--Dosimetry, electron, non-ionizing dose, optically stimulated luminescence, OSL, proton.

The aim of this work is to validate experimentally the results of the Monte Carlo Recoil Energy Determination (MC-RED) nuclear physics code used to determine the deposited energy in a silicon volume taking into account the probabilistic approach of the physical phenomenon. A silicon sensor has been used to measure the deposited energy spectrum after an irradiation with a 14 MeV neutron source. Neutrons of 14 MeV were produced by the SAMES accelerator of the Valduc CEA research center. The experimental results were compared with the one obtained by the MC-RED code in the same silicon volume. To compare experiment and simulations, it requires that the complete neutron field be specified. We have to take into account the facility cell environment. Nuclear simulations were performed with the MCNP code to determine with accuracy the energy spectra of neutrons and gamma rays produced by this facility on the sensor. It is shown that the contribution of secondary neutrons is not negligible. Index Terms--Neutron-silicon interactions, neutron source, nuclear physics code, silicon detector, single event upset.

A physical model of the dose-rate effect in bipolar junction transistors is proposed, based on competition between trapping and recombination of radiation-induced carriers in the oxide. The initial recombination of the carriers is considered in this model, taking into account the temperature effect. The general trends obtained with this model are in very good agreement with experimental data. It is also shown that the dose rate effect depends significantly on oxide quality. Index Terms--Bipolar junction transistor, enhanced low-dose-rate sensitivity (ELDRS), elevated temperature irradiation, initial recombination, switching experiment, total dose.

The impact of the bias condition during irradiation on the total-dose response of a bipolar voltage comparator is investigated. Experimental results obtained with input pins biased asymmetrically during irradiation exhibit completely different total-dose response compared to irradiation with all pins grounded. Circuit analysis shows that asymmetrical biasing of the input stage creates a mismatch of the gain degradation in the transistors constituting the differential pair. Index Terms--Bipolar analog circuits, circuitry, integrated circuits (ICs), linear voltage comparator, total dose.

This paper investigates the single event upset sensitivity of Bulk SRAMs for terrestrial applications. The technology sensitivity is analyzed with both quasi-monoenergetic neutron and proton experiments in an energy range from 14 to 180 MeV. Analytical and simulation based correction methods of the neutron cross section are presented and validated. Then, neutron and proton cross section are compared. Soft Error Rate (for the terrestrial neutron spectrum) calculated with either proton or quasi-monoenergetic neutron data are also presented and compared. Index Terms--Bulk technologies, neutron and proton effects, soft error rate (SER), single-event upset (SEU).

A contribution to the understanding of total dose degradation using both AC small signal analysis and DC analysis in linear bipolar circuits is proposed. The reasoning is illustrated step by step on the basis of experimental results obtained on the LM 139. It is shown that the input stage is mostly responsible for the degradation up to 20 krad. Above 20 krad, the total degradation is due to a combination of the input and the output stage degradation. The amplifier stage does not play a significant role in the circuit degradation. Index Terms--Bipolar analog circuits, circuitry, integrated circuits (ICs), linear voltage comparator, total dose.

The charge sharing quantification in the case of neutron induced SEUs in a 130 nm bulk SRAM is presented. Conclusions on its contribution to the soft errors sensitivity evaluation using Monte-Carlo codes are underlined. Index Terms--Bulk, charge sharing, diffusion, neutron, SEU, SRAM, TCAD simulations.

This paper presents the new detailed analysis of the secondary ion effect analytical version that allows fast and accurate calculation of neutron, proton and heavy ion cross sections in SRAM based memories. The advantage of this new version is a better determination of the input parameters using heavy ion data. A validation is presented by comparing simulation results with experimental data for technology from 600 to 180-nm. Index Terms--Cross section prediction, SEU, SRAM.

This paper presents a new way of investigation using the laser method. It is based on laser threshold mappings of electronic devices. The main idea is to use these mappings in order to extract physical parameters, for instance sizes and shapes of the different sensitive areas of a component. These parameters can be used as input parameters for analytical or Monte Carlo calculation codes in order to predict the behavior of sensitive components towards radiations. Index Terms--Calculation codes, laser mappings, SEU, SRAM.

The low-dose-rate response of five bipolar integrated circuits is evaluated on the basis of switching experiments. Such experiments consist of performing first a high-dose-rate irradiation followed by a low-dose-rate irradiation. Based on these experiments, a time-saving method to predict the low-dose-rate degradation of bipolar linear microcircuits is proposed. This approach provides a good estimate of the low-dose-rate degradation. Index Terms--Bipolar technology, dose rate, enhanced low-dose-rate sensitivity (ELDRS), integrated circuit, switching experiment, total dose.

A version of the Optically Stimulated Luminescence (OSL) sensor specifically developed to monitor the dose online in radiation facilities is presented and calibrated with [sup.60]Co. The lowest dose measurable at the extremity of a 20 m cable is 0.3 mGy. Index Terms--Online dosimetry, Optically Stimulated Luminescence (OSL), protons.

This paper investigates the sensitivity of SOI and Bulk SRAMs to neutron irradiations with energies from 14 to 500 MeV. The technology sensitivity is analyzed with both experiments and Monte Carlo simulations. In particular, simulations include the nuclear interactions of neutrons with both silicon and oxygen nuclei In-St and n-O), in order to investigate the influence of isolation upper layers on the device sensitivity. The device cross-sections are analyzed for mono-energetic neutron irradiations and discussed in terms of nuclear interaction type (n-St and n-O) and distribution of the secondary ion recoils. We also investigate the dimensions of the interaction volume around the sensitive cell as a function of the device architecture. Index Terms--Bulk technologies, SOI technologies, neutron effects, soft error rate (SER), single-event upset (SEU), Monte Carlo methods.

This paper presents a new 3D methodology to simulate Multiple Bit Upsets in commercial SRAMs. Experiments are performed at the Los Alamos neutron facility on 90, 130, and 250 nm SRAMs and compared to Monte-Carlo simulations. A discussion on ions inducing MBUs is also proposed. Index Terms--Bulk, diffusion, Monte-Carlo, multiple bit upsets (MBU), neutron, SEU, SRAM.

A reliable criterion for SEU occurrence simulation is presented. It expresses the relationship existing at threshold between the magnitude and duration of the ion-induced parasitic pulse. This criterion can be obtained by both three-dimensional device and SPICE simulations. Using this criterion, the simulated and experimental SER on 130 and 250 nm technologies are shown to be in good agreement.

This paper investigates the sensitivity of bulk technologies in the terrestrial neutron environment as a function of technology scaling. Their sensitivity is analyzed with both experiments and Monte Carlo simulations. The soft error rate (SER) of future technology generations is extrapolated, analyzed and discussed on the basis of different parameters such as the interaction volume, the secondary ion species and the incident neutron energy ranges. Index Terms--Bulk technologies, Monte Carlo methods, neutron effects, soft error rate, single-event upset, SRAM chips.

A methodology to quantify the single event upset (SEU) cross section in a simplified random access memory (RAM) device for neutron energy ranging from 10 MeV up to 150 MeV has been proposed and accounts for both heavy and light ions. Usual Monte Carlo method is shown to be suitable for the contribution of short range ions but not for long range ones such as alphas. An analytical approach to investigate the contribution of these long ranges particles on SEU cross section is given. It uses the efficient ions distribution which is the probability that a neutron produces an ion able to deposit a given energy over a given distance after a given range. Results show, for accurate calculations in sensitive RAMs, alphas might be considered up to 100 [micro]m from the sensitive volume. Index Terms--Efficient ion distribution, long range ions, monte carlo, neutron.

The total-dose response of bipolar microcircuits is investigated. A recovery of the degradation is observed for high total dose in the saturation region. The circuit response in this region is studied based on room temperature annealing. The role of the electric feld is studied and the results are discussed in terms of hardness assurance. Index Terms--Bipolar transistor, device characterization, dose rate, hardness assurance, linear microcircuit, saturation region, total dose.

The influence of an electrostatic barrier in the oxide bulk on the radiation-induced degradation of bipolar technologies is investigated by performing a thermal annealing operation before switching the dose rate from high to low. It is shown that, in our test conditions, no significant electrostatic barrier effect is at play in the device degradation. Index Terms--Bipolar, dose, dose rate, enhanced low dose rate sensitivity (ELDRS), ICs, thermal annealing.

The loss of sensitivity induced by the displacement damage effect on the optically stimulated luminescent dosimeter is investigated. A new architecture is proposed and successfully tested to harden the sensor at system level. Index Terms--Dosimeter, dosimetry, hardening, OSL, sensor.

Experiments conducted at high and low dose rates show that the total dose response of bipolar linear integrated circuits is influenced by mechanical stress. The role of mechanical stress on enhanced low dose rate sensitivity is discussed. Index Terms--Bipolar ICs, dose, dose rate, enhanced low dose rate sensitivity (ELDRS), mechanical stress, passivation layer, strain, total dose.

The off-NMOS and off-PMOS transistor single-event upset (SEU) sensitivities are studied in a 0.6-[micro]m SRAM. In some cases, the off-PMOS sensitivity is shown to be similar to the off-NMOS one. This could affect SEU rate calculations. Index Terms--Electric field, NMOS, PMOS, SEU, SRAM, transistor sensitivity.

A model is proposed to evaluate both the optimum temperature (leading to the maximum degradation of the device) and the degradation induced by high-temperature irradiation at a given dose rate on n-p-n bipolar-junction transistors. Using a genetic algorithm, the model parameters are extracted by fitting experimental curves. The model and experimental results, presented for two different devices, are in good agreement. The fitting procedure is discussed. Index Terms--Bipolar transistor, dose, dose effect, dose rate, enhanced low-dose rate sensitivity (ELDRS), elevated temperature irradiation, genetic algorithm, interface traps, model, n-p-n transistor, optimum irradiation temperature, oxide trapped charges.

Proton-irradiation results ranging from 17 MeV to 100 MeV are presented for silicon commercial off-the-shelf charge-coupled devices. Mean degradation of the dark current and the dark-signal nonuniformity are analyzed. A good linearity between proton-nonionizing energy loss and the mean dark-signal degradation is obtained. A method to determine parameters required by the Marshall Method prediction is proposed. This method is based on the three experimental and theoretical moments. An excellent agreement is obtained with the experimental degradation. The last step is to perform the method on a continuous proton spectrum. Prediction of dark-signal behavior is in a good agreement with experimental data. Index Terms--CCD, DSNY, displacement damage, NIEL.

The effect of high-temperature irradiation on commercial bipolar junction transistors has been studied for four dose rates. The experimental data presented in this paper show two base current degradation peaks as a function of irradiation temperature. An attempt to physically explain the obtained experimental results is proposed. This explanation is based on the difference in the enhancement-annealing kinetic of the elementary processes at play. The combined effects of high irradiation temperatures and dose rate are also discussed. Index Terms--25 [degrees]C to 170 [degrees]C, annealing, bipolar transistors, current gain, elevated irradiation temperatures, high dose rate irradiation, interface states, NPN transistors, optimum temperature irradiation, oxide trapped charge, radiation hardness, radiation-induced current gain degradation, radiation-induced dopant deactivation, radiation responses, Si.

We have studied the effect of proton irradiation with energies from 21 to 200 MeV on commercial optocouplers. The basic degradation mechanisms for such devices are reviewed. Our experimental results are described. Using the concept of displacement damage dose, we propose a new approach to analyze the results. Index Terms--Damage dose, nonionizing energy loss (NIEL).

We irradiated and then annealed 4049 CMOS inverters from four different manufacturers using the isochronal annealing method. From one manufacturer to another, the experimental results show completely different device behavior during the annealing. From these results, the use of the isochronal annealing method to screen the devices on the basis of the failure risk is discussed. Moreover, we show how experimental isochronal annealing under bias can allow detection of the rebound effect in devices. Index Terms--Cots, isochronal annealing, prediction, rebound.

For the first time, optically stimulated luminescent (OSL) dosimeters have been irradiated at CERN with high-energy particles. Two experiments with existing OSL films are presented: measuring the dose delivered by 3.66-GeV negative pions and mapping the intensity profile of a 23-GeV proton beam. An on-line dosimeter is also presented and applied to the monitoring of the dose delivered by a 500-MeV electron beam. The results are discussed with regards to the specific concerns raised by high doses and high energies. Index Terms--Dose map, high-energy protons, optically stimulated luminescent (OSL) dosimetry.

A physical model is developed to quantify the contribution of oxide-trapped charge to enhanced low-dose-rate gain degradation in bipolar junction transistors. Multiple-trapping simulations show that space charge limited transport is partially responsible for low-dose-rate enhancement. At low dose rates, more holes are trapped near the silicon-oxide interface than at high dose rates, resulting in larger midgap voltage shifts. The additional trapped charge near the interface causes an exponential increase in excess base current and a resultant decrease in current gain for some NPN bipolar technologies. Space charge effects also may be responsible for differences in interface trap formation at low and high dose rates.

A new method for accelerated prediction of the longterm thermal annealing of bulk oxide trapped charge in the low dose rate space environment was presented in a previous paper. This method, based on the thermal detrapping characteristics is briefly reviewed. From a single experimental isochronal curve, the long term isothermal behavior of the device is predicted and compared with an experimental isothermal curve. Four different devices, obtained from four different manufacturers, were examined to demonstrate the validity of this method. In all four cases, the predicted long-term thermal behavior is in good agreement with experimental results. This method's application is discussed for space missions.

The feasibility of an integrated sensor based on Optically Stimulated Luminescence (OSL) dosimetry is demonstrated. The principle and the basic structure are reviewed. A lab demonstrator was realized and a board designed to operate the sensor at different doses and doses rates. The first calibrations are presented and discussed.

In this paper, a procedure is proposed to predict the long-term behavior of commercial metal oxide semiconductor field effect transistors not only after irradiation, as previously published, but during irradiation at a given temperature. This procedure is validated on three different commercial power MOSFETs. In all three cases, the predicted and experimental results are in good agreement. The application of the procedure is discussed.

In a previous paper, a method was proposed to predict the thermal annealing of irradiated devices from a single experimental isochronal curve. In this paper, the method is applied to four different power MOSFETs. It is shown that for one of the devices the method can not be applied, whereas for the other three devices, the one-year isothermal behavior is predicted with good accuracy. The predicted and experimental isothermal curves are compared for temperatures of 60 [degrees] C and 90 [degrees] C. The range of validity of this method is discussed.

High energy electron dose mapping is a complex subject. Experiments using Optically Stimulated Luminescent films behind various shielding structures and dual inline packages are presented. The dose-depth deposition in an epoxy package is also investigated. These results are compared with PENELOPE transport code calculations.