J. Boch

Criterion for SEU occurrence in SRAM deduced from circuit and device Simulations in case of neutron-induced SER

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.

Physical Model for the Low-Dose-Rate Effect in Bipolar Devices

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

Estimation of low-dose-rate degradation on bipolar linear integrated circuits using switching experiments

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.

Dose rate effects in bipolar oxides : Competition between trap filling and recombination

Predicting the low-dose-rate degradation of bipolar technologies is one of the main issues for circuits intended for use in the ionizing-radiation environment of space because of the enhanced low-dose-rate sensitivity (ELDRS). In this letter, ELDRS is shown to be related to competition between trapping and recombination of radiation-induced carriers in the oxide. The presented model is shown to be in good agreement with experimental data. It is also shown that this effect is strongly dependent on the oxide quality.

Prediction of Multiple Cell Upset Induced by Heavy Ions in a 90 nm Bulk SRAM

The PHISco simulation tool was known to be able to predict the SEU cross section for incident ions. This tool is improved in this work to also predict the MCU rate. Experimental and predicted results are shown to be in good agreement on a 90 nm bulk SRAM. The simulated SRAM structure includes the N-well, which is known to be a barrier to the charge carriers.

Effect of switching from high to low dose rate on linear bipolar technology radiation response

The degradation of discrete and integrated-circuit bipolar technologies irradiated at High Dose Rate (HDR) and then switched to Low Dose Rates (LDR) is studied. It is shown that the degradation rate of switched devices is equal to that found at low dose rates for all the tested devices.

Impact of Total Ionizing Dose on the Analog Single Event Transient Sensitivity of a Linear Bipolar Integrated Circuit

Total ionizing dose (TID) strongly affects the single event transient (SET) sensitivity of a bipolar linear voltage comparator (LM139). The general rule that transistors in the non-conducting state are the most sensitive to SETs was verified, with some exceptions. The mechanisms responsible for those exceptions were identified and explained using circuit analysis. In the non typical behavior, a correlation of the degradation of the amplifier stages with the shape of the transient output signal was established. Following total dose exposure the SETs generally exhibit a reduction in amplitude due to the degradation of the slew rate. However, in some cases the transient signal is amplified because degradation of either the current source or of the current gain of some transistors forces the output transistor to the edge of conduction, so that it behaves like a voltage amplifier and amplifies the parasitic transient signal. Laser testing demonstrates that ASET sensitivity also is affected by TID degradation of transistors that are not directly hit by the laser.

Innovative Simulations of Heavy Ion Cross Sections in 130 nm CMOS SRAM

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.

Neutron-induced SEU in SRAMs: Simulations with n-Si and n-O interactions

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 (n-Si 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-Si 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.

The Use of a Dose-Rate Switching Technique to Characterize Bipolar Devices

The enhanced radiation sensitivity exhibited at low dose rate by many bipolar devices remains one of the main concerns for spacecraft reliability. As an accelerated test technique, a new approach based on dose-rate switching experiments has been proposed to characterize bipolar devices. The foundations of this approach are detailed and guidelines for its use are given.