Heavy Ion Test Data Research Articles

Prediction of proton single event upset sensitivity based on heavy ion test data in nanometer hardened static random access memory

In order to evaluate the radiation tolerance to proton single event effect(SEE) in nanometer dual interlocked cell (DICE) hardening device accurately, single event upset (SEU) linear energy transfer (LET) threshold at heavy ion normal and tilt incidence, and the worst case SEU orientational angle are acquired based on the analysis of heavy ion SEU testing data in 65 nm dual DICE static random access memory (SRAM). It is proved that dual DICE design is effective for improving the LET threshold against SEU. Howerer, heavy ion tilt incidence at the worst orientational angle will significantly reduce the SEU threshold and increase the SEU cross section. The worst orientational angle for SEU in DICE SRAM is the large tilting angle along the well. The maximum LET value and the emission angle distribution of secondary particle induced by the nuclear reaction between protons with different energy and layers with different multiple metallization are obtained by using Monte-Carlo simulation. The maximum LET value of secondary particle from proton-copper spallation reaction is higher than 15 MeV·cm<sup>2</sup>/mg for 100 MeV and 200 MeV protons. Secondary particles with the maximum energy and longest range are emitted preferentially in the forward direction. Proton SEU sensitivity is further predicted through combining heavy ion test data with Monte-Carlo simulation. Proton SEU test data verify the effectiveness of the prediction method and the accuracy of the prediction results. The research results indicate that the tolerance of nanometer DICE hardening technique against proton SEU will be overestimated if SEE evaluation test is carried out with only 100 MeV proton accelerator or normal incidence. Proton single event upset in nanometer dual DICE SRAM has an evident dependence on tilt angle and orientational angle. By adopting the above prediction method, whether proton SEE test needs performing or not in nanometer radiation-hardening device can be judged and screened. The requirements for the maximum energy of proton accelerator can be ascertained. In order to ensure that the devices are applied to space with high reliability, SEE test should be carried out including tilt incidence at the worst orientational angle in nanometer DICE hardening device in the process of heavy ion and proton SEE test evaluation.

Single-Event Latchup in a CMOS-Based ASIC Using Heavy Ions, Laser Pulses, and Coupled Simulation

In this paper, we investigate single-event latchup (SEL) in complementary metal–oxide–semiconductor (CMOS)-based flip-flop structures combining heavy ions, laser pulses, and simulation. In the framework of exploring the use of lasers for single-event sensitivity studies, we have compared SEL cross sections obtained with these techniques. The spatial resolution of the laser provided the sensitivity map of a flip-flop cell using various laser energies, highlighting the origin of SEL occurrence in link with topology. Latchup current distributions were then intensely analyzed over the cell and the whole application-specific integrated circuit (ASIC) to understand their sources, supported by simulation. A cross correlation was performed with heavy-ion test data to show the potential and the limits of laser techniques for both global and detailed SEL analysis.

Qcrit-independent model method for proton SEU analysis

An improved model for device proton SEU cross section simulation is established totally based on heavy ion test data. The model is deduced from the assumption that an injecting heavy ion with a certain LET value will just generate a SEU cross section value corresponding to the LET value at the heavy ion test data. Based on the assumption, the model has special sub-volume collection efficiency, which makes the SEU cross section simulation result through the model independent of critical charge (Qcrit). The modeling method is verified by heavy ion and proton test data of Xilinx XC2V1000 and XC4VSX55 FPGA. The difference of proton SEU cross section between simulation result and test data is less than 69% above 40 MeV of proton.

Prediction of proton-induced SEE error rates for the VATA160 ASIC

We predict proton single event effect (SEE) error rates for the VATA160 ASIC chip on the Dark Matter Particle Explorer (DAMPE) to evaluate its radiation tolerance. Lacking proton test facilities, we built a Monte Carlo simulation tool named PRESTAGE to calculate the proton SEE cross-sections. PRESTAGE is based on the particle transport toolkit Geant4. It adopts a location-dependent strategy to derive the SEE sensitivity of the device from heavy-ion test data, which have been measured at the HI-13 tandem accelerator of the China Institute of Atomic Energy and the heavy-ion research facility in Lanzhou. The AP-8, SOLPRO, and August 1972 worst-case models are used to predict the average and peak proton fluxes on the DAMPE orbit. Calculation results show that the averaged proton SEE error rate for the VATA160 chip is approximately 2.17 × 10−5/device/day. Worst-case error rates for the Van Allen belts and solar energetic particle events are 1–3 orders of magnitude higher than the averaged error rate.

Monte Carlo predictions of proton SEE cross-sections from heavy ion test data**Supported by National Natural Science Foundation of China (11179003, 10975164, 10805062, 11005134)

The limits of previous methods prompt us to design a new approach (named PRESTAGE) to predict proton single event effect (SEE) cross-sections using heavy-ion test data. To more realistically simulate the SEE mechanisms, we adopt Geant4 and a location-dependent strategy to describe the physics processes and the sensitivity of the device. Cross-sections predicted by PRESTAGE for over twenty devices are compared with the measured data. Evidence shows that PRESTAGE can calculate not only single event upsets induced by indirect proton ionization, but also direct ionization effects and single event latch-ups. Most of the PRESTAGE calculated results agree with the experimental data within a factor of 2–3.

Single-Event Transient Measurements on a DC/DC Pulse Width Modulator Using Heavy Ion, Proton, and Pulsed Laser

This paper discusses multiple methods of Single-Event Transient (SET) measurements on a commercial DC/DC Pulse Width Modulator (PWM). Heavy ion, proton, and pulsed laser are used in the experiments. The correlations between the heavy ion, pulsed laser and proton data are analyzed and presented. A proton cross-section model is used to derive proton cross-section from heavy ion test data. The calculated result is close to the real proton data, which means the heavy ion and proton data fit well. The relationship between pulsed laser and proton are also analyzed through heavy as a medium.

Circuit-Level Layout-Aware Single-Event Sensitive-Area Analysis of 40-nm Bulk CMOS Flip-Flops Using Compact Modeling

A circuit-level layout-aware single-event simulation capability is presented. Multiple 40-nm bulk CMOS flip-flops are analyzed to determine single-event upset (SEU) sensitive area. Comparisons between simulation results and broadbeam heavy-ion test data show excellent agreement. Simulations of single-event strikes over the entire flip-flop layout can be performed in less than 1 h.

Extension of a Proton SEU Cross Section Model to Include 14 MeV Neutrons

A model for estimating proton SEU cross sections from heavy-ion test data has been extended to include 14 MeV neutrons. Accuracy is less consistent for neutrons, but predictions can still be used for upper bounds.

Proton SEU cross sections derived from heavy-ion test data

Many papers have presented models for estimating proton single event upset (SEU) cross sections from heavy-ion test data, but all rigorous treatments to date are based on the sensitive volume (SV) model for charge collection. Computer simulations have already shown that, excluding devices utilizing physical boundaries for isolation, there is no well-defined SV. A more versatile description of charge collection, which includes the SV model as a special case, utilizes a charge-collection efficiency function that measures the effect that the location of ionization has on collected charge. This paper presents the first rigorous analysis that uses a generic charge collection efficiency function to relate proton to heavy-ion cross sections. The most practical result is an upper bound for proton SEU or single event latchup (SEL) cross sections, which requires no information about the charge-collection efficiency function, except that it exists. In addition, some models previously presented by others are reproduced (or, in one case, extended) by applying the general theory to special cases. The similarities and differences between a variety of models become clear when the models are recognized to be special cases or variations of this general theory.

SRAM based re-programmable FPGA for space applications

An SRAM (static random access memory)-based reprogrammable FPGA (field programmable gate array) is investigated for space applications. A new commercial prototype, named the RS family, was used as an example for the investigation. The device is fabricated in a 0.25 /spl mu/m CMOS technology. Its architecture is reviewed to provide a better understanding of the impact of single event upset (SEU) on the device during operation. The SEU effect of different memories available on the device is evaluated. Heavy ion test data and SPICE simulations are used integrally to extract the threshold LET (linear energy transfer). Together with the saturation cross-section measurement from the layout, a rate prediction is done on each memory type. The SEU in the configuration SRAM is identified as the dominant failure mode and is discussed in detail. The single event transient error in combinational logic is also investigated and simulated by SPICE. SEU mitigation by hardening the memories and employing EDAC (error detection and correction) at the device level are presented. For the configuration SRAM (CSRAM) cell, the trade-off between resistor dc-coupling and redundancy hardening techniques are investigated with interesting results. Preliminary heavy ion test data show no sign of SEL (single event latch-up). With regard to ionizing radiation effects, the increase in static leakage current (static I/sub CC/) measured indicates a device tolerance of approximately 50 krad(Si).

Further development of the Heavy Ion Cross section for single event UPset: model (HICUP)

HICUP models the angular dependent heavy ion upset cross section. It pulls together many of the parameters and concepts used to characterize the Single Event Upset (SEU) phenomena, unifying them in a single cohesive model. HICUP is based on a Rectangular Parallelepiped (RPP) geometry for the sensitive volume and the Weibull density function for the upset threshold energy. Excellent agreement is obtained between the model and heavy ion test data. HICUP is used to derive the correct scaling laws for transforming angular cross section data to normal incidence, reconciling two previously proposed inverse cosine scaling corrections. The angle-integrated HICUP model, I-HICUP, is used in Galactic Cosmic Ray (GCR) upset rate calculations with results nearly identical to the Space Radiation code. Letaw has produced an automated SEU parameter fitting routine based on HICUP and the /spl chi//sup 2/ method. It ferrets out the best-fit critical SEU parameters embedded within the raw angular test data, including charge collection depth and funnel length. His method couples directly to the upset rate calculation in a self-consistent manner eliminating the need to arbitrarily assume a device depth. Results of this new procedure are presented.

Estimation of proton upset rates from heavy ion test data (ICs)

A simple method of calculating the proton upset rates from heavy ion test data is presented. Given the approximations made, particularly in fitting a curve to the experimental data, the error made in determining the upset rate can be as large as four or six. It is clear from this model that ICs with heavy ion thresholds >10 MeV/(mg/cm/sup 2/) will probably not upset with protons. In critical applications ICs with LET thresholds less than 10 MeV/(mg/cm/sup 2/) should be tested with protons, or at the minimum careful heavy ion test data should be taken in the low LET regions (for heavy ion upset considerations as well as proton upset).< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A model for proton-induced SEU

The authors present a method for predicting proton-induced single-event upset (SEU) rates in devices exposed to given proton fluxes, within a particular spacecraft shielding. The approach uses experimental heavy-ion cross-section data, combined with nuclear reaction calculations, in order to determine the proton-induced SEU cross section versus proton energy relationship. Calculations for two devices, the Fairchild 93L422 RAM and the Intel 2164A dynamic RAM, for which heavy-ion test data were available, are presented and compared with other theoretical results and with ground-based experimental data. Available on-orbit SEU data are then compared with the present predictions. Predicted SEU rates for both protons and cosmic rays at various 60 degrees circular orbits are also compared. Good agreement is found in all cases.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Methods for Calculating SEU Rates for Bipolar and NMOS Circuits

Computer codes developed at Clarkson for simulating charge generation by proton-induced nuclear reactions in well-defined silicon microstructures can be used to calculate SEU rates for specific devices when the critical charge and the dimensions of all SEU sensitive junctions on the device are known, provided one can estimate the contribution from externally-generated charge which enters the sensitive junction by drift and diffusion. Calculations for two important bipolar devices, the AMD 2901B bit slice and the Fairchild 93L422 RAM, for which the dimensions of the sensitive volumes were estimated from available heavy-ion test data, have been found to be in agreement with experimental data. Circuit data for the Intel 2164A, an alpha sensitive dRAM, was provided by the manufacturer. Calculations based on crude assumptions regarding which nuclear recoils and which alphas trigger upsets in the 2164A were found to agree with experimental data.