Hak S. Kim

Effectiveness of Internal Versus External SEU Scrubbing Mitigation Strategies in a Xilinx FPGA: Design, Test, and Analysis

A comparison of two scrubbing mitigation schemes for Xilinx field programmable gate array devices is presented. The design of the scrubbers is briefly discussed along with an examination of mitigation limitations. Heavy ion data are then presented and analyzed.

Impact of Low-Energy Proton Induced Upsets on Test Methods and Rate Predictions

Direct ionization from low energy protons is shown to cause upsets in a 65-nm bulk CMOS SRAM, consistent with results reported for other deep submicron technologies. The experimental data are used to calibrate a Monte Carlo rate prediction model, which is used to evaluate the importance of this upset mechanism in typical space environments. For the ISS orbit and a geosynchronous (worst day) orbit, direct ionization from protons is a major contributor to the total error rate, but for a geosynchronous (solar min) orbit, the proton flux is too low to cause a significant number of events. The implications of these results for hardness assurance are discussed.

SEE and TID Characterization of an Advanced Commercial 2Gbit NAND Flash Nonvolatile Memory

An advanced commercial 2Gbit NAND flash memory (90 nm technology, one bit/cell) has been characterized for TID and heavy ion SEE. Results are qualitatively similar to previous flash results in most respects, but we also detected a new dynamic failure mode

An investigation of the origins of the variable proton tolerance in multiple SiGe HBT BiCMOS technology generations

This paper presents the first investigation of the physical origins of the observed variable proton tolerance in multiple SiGe HBT BiCMOS technology generations. We use the combination of an extensive set of newly measured proton data on distinct SiGe HBT BiCMOS technology generations, detailed calibrated 2-D MEDICI simulations for both the SiGe HBT and Si CMOS devices, as well as reverse-bias emitter-base and forward-bias electrical stress data to aid the analysis. We find that the scaling-induced increase in the emitter-base electric field under the spacer oxide in the SiGe HBT is primarily responsible for the degraded radiation tolerance with technology scaling, while the decrease in shallow-trench thickness is largely responsible for the improved nFET radiation tolerance with technology scaling.

Evidence for angular effects in proton-induced single-event upsets

Historically, proton-induced single-event effects (SEES) ground test data are collected independent of the orientation of the microelectronic device to the proton beam direction. In this study, we present experimental and simulation evidence that shows an effect of over an order of magnitude on the proton-induced single-event upset (SEU) cross section when the angle of incidence of the proton beam is varied. The magnitude of this effect is shown to depend on the incidence proton energy and the device critical charge. The angular effect is demonstrated for Silicon-On-Sapphire and Silicon-On-Insulator technologies, but would not necessarily be limited to these technologies.

Characterizing SRAM Single Event Upset in Terms of Single and Multiple Node Charge Collection

A well-collapse source-injection mode for SRAM SEU is demonstrated through TCAD modeling. The recovery of the SRAMs state is shown to be based upon the resistive path from the p+ -sources in the SRAM to the well. Multiple cell upset patterns for direct charge collection and the well-collapse source-injection mechanisms are predicted and compared to SRAM test data.

Emerging optocoupler issues with energetic particle-induced transients and permanent radiation degradation

Radiation-induced permanent degradation and single event transient effects for optocouplers are discussed in this paper. These two effects are independent to the first order and will be addressed separately. Displacement damage-induced degradation of optocoupler current transfer ratio is reviewed. New data are presented that show the importance of application specific testing and that generalized quantification of optocoupler CTR degradation can lead to incorrect predictions of actual circuit performance in a radiation environment. Data are given for various circuit loading and drive current parameters. Previous work that introduces the idea that two mechanisms exist for inducing transients on the optocoupler output is discussed. New data are presented that extends the evidence of this dual mechanism hypothesis. In this work measurements show that single event transient cross sections and transient propagation varies with circuit filtering. Finally, we discuss utilization of the optocouplers in the space environment. New data are applied to two examples: one on permanent degradation and the other on single event transient rates in high bandwidth applications.

Current single event effects and radiation damage results for candidate spacecraft electronics

We present data on the vulnerability of a variety of candidate spacecraft electronics to proton and heavy ion induced single event effects, proton-induced damage, and total ionizing dose. Devices tested include optoelectronics, digital, analog, linear bipolar, hybrid devices, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and DC-DC converters, among others.

Energy dependence of proton damage in AlGaAs light-emitting diodes

We measure the energy dependence of proton-induced LED degradation using large numbers of devices and incremental exposures to gain high confidence in the proton energy dependence and device-to-device variability of damage. We compare single versus double heterojunction AlGaAs technologies (emitting at 880 nm and 830 nm, respectively) to previous experimental and theoretical results. We also present a critical review of the use of nonionizing energy loss in AlGaAs for predictions of on-orbit degradation and assess the uncertainties inherent in this approach.

Proton-induced transients in optocouplers: in-flight anomalies, ground irradiation test, mitigation and implications

We present data on recent optocoupler in-flight anomalies and the subsequent ground test irradiation performed. Discussions of the single event mechanisms involved, transient filtering analysis, and design implications are included. Proton-induced transients were observed on higher speed optocouplers with a unique dependence on the incidence particle angle. The results indicate that both direct ionization and nuclear reaction-related mechanisms are responsible for the single events observed.