Showing papers by "Robert A. Reed published in 2010"
TL;DR: In this paper, a Monte Carlo approach for estimating the frequency and character of single event effects based on a combination of physical modeling of discrete radiation events, device simulations to estimate charge transport and collection, and circuit simulations to determine the effect of the collected charge.
Abstract: In this paper, we describe a Monte Carlo approach for estimating the frequency and character of single event effects based on a combination of physical modeling of discrete radiation events, device simulations to estimate charge transport and collection, and circuit simulations to determine the effect of the collected charge. A mathematical analysis of the procedure reveals it to be closely related to the rectangular parallelepiped (RPP) rate prediction method. The results of these simulations show that event-to-event variation may have a significant impact when predicting the single-event rate in advanced spacecraft electronics. Specific criteria for supplementing established RPP-based single event analysis with Monte Carlo computations are discussed.
215 citations
TL;DR: In this paper, a surface barrier detector was used to characterize the kinetic energy spectra produced by the M20B surface muon beam at TRIUMF and a Geant4 application is used to simulate the beam and estimate the energy spectrum incident on the memories.
Abstract: Experimental data are presented that show low-energy muons are able to cause single event upsets in 65 nm, 45 nm, and 40 nm CMOS SRAMs. Energy deposition measurements using a surface barrier detector are presented to characterize the kinetic energy spectra produced by the M20B surface muon beam at TRIUMF. A Geant4 application is used to simulate the beam and estimate the energy spectra incident on the memories. Results indicate that the sensitivity to this mechanism will increase for scaled technologies.
104 citations
TL;DR: In this article, the existence of pulse quenching at normal and angular incidence for designs where the pMOS transistors are in common n-wells or isolated in separate nwells.
Abstract: Heavy-ion microbeam and broadbeam data are presented for a 65 nm bulk CMOS process showing the existence of pulse quenching at normal and angular incidence for designs where the pMOS transistors are in common n-wells or isolated in separate n-wells. Experimental data and simulations show that pulse quenching is more prevalent in the common n-well design than the separate n-well design, leading to significantly reduced SET pulsewidths and SET cross-section in the common n-well design.
92 citations
TL;DR: In this paper, the authors compared SET measurements in a bulk 65-nm process with transients measured in 130-nm and 90-nm processes and found that the differences in the SET widths between test circuits can be attributed in part to differences in n-well contact area.
Abstract: Digital single-event transient (SET) measurements in a bulk 65-nm process are compared to transients measured in 130-nm and 90-nm processes. The measured SET widths are shorter in a 65-nm test circuit than SETs measured in similar 90-nm and 130-nm circuits, but, when the factors affecting the SET width measurements (in particular pulse broadening and the parasitic bipolar effect) are considered, the actual SET width trends are found to be more complex. The differences in the SET widths between test circuits can be attributed in part to differences in n-well contact area. These results help explain some of the inconsistencies in SET measurements presented by various researchers over the past few years.
80 citations
TL;DR: In this paper, Monte-Carlo radiation transport simulations are used to quantify energy deposition from δ -rays in sensitive volumes representative of future SRAM technologies, and it is shown that single and multiple δ-ray events are capable of depositing sufficient energy to cause SEUs in nonadjacent SRAM cells separated by many micrometers.
Abstract: Monte-Carlo radiation transport simulations are used to quantify energy deposition from δ -rays in sensitive volumes representative of future SRAM technologies. The results show that single and multiple δ-ray events are capable of depositing sufficient energy to cause SEUs in nonadjacent SRAM cells separated by many micrometers. These results indicate the necessity of considering the variability of the charge track structure when evaluating the single event response of these highly scaled technology nodes. These effects have important implications forradiation hardening techniques that rely upon spatial separation of critical and redundant nodes, and simulation of device and circuit level response to heavy ions with respect to ion track structure.
71 citations
TL;DR: In this paper, the presence of high-Z materials increases proton-induced charge collection cross sections for high charge collection events, and the mechanism for this effect is protoninduced fission events as shown through validated Monte Carlo simulations.
Abstract: Charge collection measurements reveal that the presence of high-Z materials increases proton-induced charge collection cross sections for high charge collection events. The mechanism for this effect is proton-induced fission events as shown through validated Monte Carlo simulations. These fission fragments are emitted isotropically in contrast to high-LET secondary particles from proton-silicon interactions which tend to be forward directed.
38 citations
02 May 2010
TL;DR: In this article, single and multiple cell upsets in a 65 nm bulk CMOS SRAM were predicted for the low energy (≪ 10 MeV) portion of the NYC neutron spectrum Scattering was identified as a significant nuclear mechanism for this regime and the consequence for multiple bit upsets was discussed.
Abstract: Predictions of single and multiple cell upsets in a 65 nm bulk CMOS SRAM are presented for the low-energy (≪ 10 MeV) portion of the NYC neutron spectrum Scattering is identified as a significant nuclear mechanism for this regime and the consequence for multiple bit upset is discussed The contribution is compared to the full spectrum
34 citations
02 May 2010
TL;DR: In this article, circuit-level simulations predict increased vulnerability of flip-flop designs and increased occurrence of single-event upsets in advanced technologies due to multi-node charge collection from single-ion strikes.
Abstract: Circuit-level simulations predict increased vulnerability of flip-flop designs and increased occurrence of single-event upsets in advanced technologies due to multi-node charge collection from single-ion strikes. This trend is examined by simulating 3D models of the flip-flops in a terrestrial neutron environment with Monte-Carlo simulations of charge generation in several technology generations.
34 citations
TL;DR: In this article, a simple, algorithmic approach for selecting N- and P-well contact densities that ensures latchup immunity while minimizing the area penalty is described. But the approach is limited to single-event latchup.
Abstract: Heavy ion data for custom SRAMs fabricated in a 45-nm CMOS technology demonstrate the effects of N- and P-well contact densities on single-event latchup. Although scaling has improved latchup robustness, process-level immunity has not been achieved, indicating a continued need for latchup mitigation techniques. A simple, algorithmic approach for selecting N- and P-well contact densities is described that ensures latchup immunity while minimizing the area penalty.
27 citations
TL;DR: In this article, the authors characterized heavy ion-induced single event latchup (SEL) in a commercially available CMOS readout integrated circuit operating at cryogenic temperatures and showed that SEL is possible when free carriers produced by an ion strike initiate an exponential increase in the free carrier density via shallow-level impact ionization (SLII).
Abstract: Heavy ion-induced single event latchup (SEL) is characterized in a commercially available CMOS readout integrated circuit operating at cryogenic temperatures. SEL observed at 24 K and below is believed to be possible when free carriers produced by an ion strike initiate an exponential increase in the free carrier density via shallow-level impact ionization (SLII). This results in a large current increase that proceeds to a sustained latched state, even though the classic condition for parasitic bipolar gain product is not met since it is much less than unity. The LET threshold for SEL is significantly lower at 20 K as compared to 300 K although the saturated cross section is 2-3 times higher at 300 K. The temperature dependence of the SEL cross section is characterized from 16-300 K. SEL behavior attributed to the classical cross-coupled parasitic bipolar model is observed from ~135-300 K, and the reduction in the SEL cross section is remarkably modest as the temperature is lowered from room temperature to ~200 K. Temperature dependent electrical latchup characterization of a 130 nm pnpn test structure also indicates a change in the latchup behavior at ~50 K consistent with the SLII mechanism.
24 citations
TL;DR: In this paper, the effects of 10-keV X-rays on MOS capacitors with SiO2 or HfO2 gate dielectrics and Al and TaSi gate metallization have been studied using the Monte Carlo simulator, MRED.
Abstract: The effects of 10-keV X-rays and 400-keV endpoint-energy bremsstrahlung X-rays on MOS capacitors with SiO2 or HfO2 gate dielectrics and Al and TaSi gate metallization have been studied using the Monte Carlo simulator, MRED. We compare these calculations with previous results in the literature obtained with other Monte Carlo and discrete ordinates codes, and with experiments on devices with SiO2 gate dielectrics, and find generally good agreement. There is a significant dose reduction in thin HfO2 layers exposed to 10-keV X-rays, when the HfO2 is surrounded by lower-Z materials (e.g., Si, Al). This dose reduction does not occur in a medium-energy bremsstrahlung X-ray environment; in that case, the dose in a HfO2 gate dielectric can be ~10 times higher than the dose in a SiO2 dielectric, for the same incident X-ray fluence. These results demonstrate the capability of MRED to assist in the evaluation of dose enhancement and reduction in regions including or nearby high-Z materials in microelectronic materials and devices.
TL;DR: In this paper, a 3D mixed-mode simulation of first-generation SiGe HBTs is presented, and a plausible answer is given to the previously unexplained issue of higher collector currents in single-transistor HBT single-event transients under positive collector bias.
Abstract: Comprehensive 3-D mixed-mode simulations, including accurate modeling of parasitic elements present in the experimental setup, resulted in close agreement between simulated and experimentally-measured heavy-ion-induced transients in first-generation SiGe HBTs. We have identified the key factors affecting previous simulations and observed experimental differences. The approach employed is also applicable to other submicron, high-speed technologies. Furthermore, we present a plausible answer to the previously unexplained issue of higher collector currents in single-transistor SiGe HBT single-event transients under positive collector bias. The new observations and conclusions facilitate improved understanding and potential mitigation options.
01 Oct 2010
TL;DR: The successor to the CREME suite of tools, CREME-MC, is a Geant4 based application intended to address the challenges associated with highly-scaled or radiation-hardened devices as discussed by the authors.
Abstract: The CREME suite of tools have been extensively used to predict the effects of cosmic rays on microelectronics in space. These tools only consider electronic stopping of ions and nuclear reactions from protons on silicon. Ion-ion physics and the inclusion of additional electronic materials are required to predict large energy deposition events. The successor to the rate prediction tools, CREME-MC, is a Geant4 based application intended to address the challenges associated with highly-scaled or radiation-hardened devices.
TL;DR: In this article, the authors report the observation of enhanced oxidation on silicon and porous silicon samples exposed in air ambient to high-dose-rate 10 keV x-ray radiation at room temperature.
Abstract: We report the observation of enhanced oxidation on silicon and porous silicon samples exposed in air ambient to high-dose-rate 10 keV x-ray radiation at room temperature. The evolution of the radiation-induced oxide growth is monitored by ellipsometry and interferometric reflectance spectroscopy. Fourier transform infrared (FTIR) spectroscopy shows the emergence of Si–O–Si stretching modes and corresponding suppression of SiHx and Si–Si modes in the porous silicon samples. The radiation response depends strongly on initial native oxide thickness and Si–H surface species. The enhanced oxidation mechanism is attributed to photoinduced oxidation processes wherein energetic photons are used to dissociate molecular oxygen and promote the formation of more reactive oxygen species.
TL;DR: In this article, high-bandwidth (16 GHz) time-resolved charge collection measurements for heavy ion irradiation of up to 70 GeV/amu are performed on low-power 6.1 Å lattice spacing InAlSb/InAs HEMT devices.
Abstract: High-bandwidth (16 GHz) time-resolved charge-collection measurements for heavy-ion irradiation of up to 70 GeV/amu are performed on low-power 6.1 Å lattice spacing InAlSb/InAs HEMT devices. Event cross sections are measured to be significantly larger than the active areas of the devices. Novel energy-dependent effects are observed.
TL;DR: In this paper, a Monte-Carlo model of the flip-flop was used to analyze the impact of multi-node charge collection within a flip flop due to a single particle strike.
Abstract: Heavy-ion measurements on 40-nm flip-flops indicate pattern dependence of cross-section resulting from local control logic upsets, such as clock nodes. A Monte-Carlo model of the flip-flop, calibrated to the heavy-ion data, is used to analyze the impact of multi-node charge collection within a flip-flop due to a single particle strike. Depending on the nodes that collect charge, multi-node charge collection can either increase or decrease the vulnerability of the cell. For neutrons, the overall effect of such events was found to be a net increase in cross-section by up to 16%.
TL;DR: In this article, a 1 GeV/amu 56Fe ion beam allows for true 90° tilt irradiations of various microelectronic components and reveals relevant upset trends at the GCR flux energy peak.
Abstract: A 1 GeV/amu 56Fe ion beam allows for true 90° tilt irradiations of various microelectronic components and reveals relevant upset trends at the GCR flux energy peak. Three SRAMs and an SRAM-based FPGA evaluated at the NASA Space Radiation Effects Laboratory demonstrate that a 90° tilt irradiation yields a unique device response. These tilt angle effects need to be screened for, and if found, pursued with radiation transport simulations to quantify their impact on event rate calculations.
TL;DR: In this paper, the authors investigate charge collection and single-event upset (SEU) in SiGe HBT devices and logic circuits using 3D device simulation and circuit simulation.
Abstract: This paper investigates cryogenic temperature charge collection and single-event upset (SEU) in SiGe HBT devices and logic circuits using 3-D device simulation and circuit simulation. Cryogenic temperature circuit simulation is enabled by a new SiGe HBT compact model developed for wide temperature range operation. Incomplete ionization was found to impact charge collection below 130 K. With cooling, collector-substrate (CS) junction peak current ICS and integral charge QCS first increase, and then decrease below 130 K. Circuit SEU immunity is found to be nearly independent of temperature above 150 K and improve with further cooling, suggesting no additional hardening is required for cryogenic temperature operation.
TL;DR: In this article, the radiation response of a 0.25 μm silicon-on-sapphire CMOS technology is characterized at the transistor and circuit levels utilizing both standard and enclosed layout devices.
Abstract: The radiation response of a 0.25 μm silicon-on-sapphire CMOS technology is characterized at the transistor and circuit levels utilizing both standard and enclosed layout devices. The threshold-voltage shift is less than 170 mV and the leakage-current increase is less than 1 nA for individual standard-layout nMOSFET and pMOSFET devices at a total dose of 100 krad(SiO2). The increase in power supply current at the circuit level was less than 5%, consistent with the small change in off-state transistor leakage current. The technology exhibits good characteristics for use in the electronics of the ATLAS experiment at the Large Hadron Collider.
TL;DR: In this paper, the authors present a detailed theoretical analysis of the degradation mechanism in InAs/AlSb high-electron mobility transistors (HEMTs) and show that recoverable degradation does not require the presence of hot carriers in the vicinity of the defects but the degradation is enhanced when the injected holes become more energetic.
Abstract: Recent observations of electrical stress-induced recoverable degradation in InAs/AlSb high-electron mobility transistors (HEMTs) have been attributed to metastable defects in the AlSb layer generated by the injected holes. Here we present a detailed theoretical analysis of the degradation mechanism. We show that recoverable degradation does not require the presence of hot carriers in the vicinity of the defects but the degradation is enhanced when the injected holes become more energetic. The metastable degradation arises without the presence of an energy barrier. A comprehensive survey of candidate defects suggest that substitutional and interstitial oxygen are responsible for the degradation. Therefore, reducing the oxygen contamination during device fabrication is likely to significantly improve the reliability of InAs/AlSb HEMTs.
01 Oct 2010
TL;DR: In this article, a customized cryogenic test system for use in in situ single-event radiation tests on semiconductor devices at cryogenic temperatures is presented, which is designed for use with either liquid nitrogen or liquid helium as cryogens, depending on the desired lower temperature limit.
Abstract: Details of a customized cryogenic test system for use in in situ single-event radiation tests on semiconductor devices at cryogenic temperatures are presented. The lightweight portable system is designed for performing heavy-ion broadbeam single-event radiation testing at different beam facilities. It is designed for use with either liquid nitrogen or liquid helium as cryogens, depending on the desired lower temperature limit. A controlled heating system on the inside allows for single-event radiation tests as a function of temperature. To enable single-event strikes at angles, the device under test can be rotated about a vertical axis without having to break vacuum. Electrical connectivity to the device under test is provided through six fully customizable hermetically sealed connecting ports. The system has been used to conduct single-event tests over temperature on a test circuit fabricated in IBM CMOS 130 nm technology. Single-event transient pulse widths were found to increase by up to 30% as the temperature was varied from −135 °C to +20 °C. Device simulations indicate that single-event-induced parasitic bipolar transistor turn-on in the n-well of PMOS transistors is responsible for the observed increase in pulse widths across the temperature ranges considered.
TL;DR: In this article, an analytical framework based on Markov chains and queue theory is presented for computation of alpha-particle-induced soft-error rates of a flip-flop operated in the subthreshold regime.
Abstract: Radiation-induced soft errors have been a reliability concern for logic integrated circuits since their emergence. Feature-size and supply-voltage reduction require the analysis of soft-error sensitivity as a function of technology scaling. In this paper, an analytical framework based on Markov chains and queue theory is presented for computation of alpha-particle-induced soft-error rates of a flip-flop operated in the subthreshold regime. The proposed framework is capable of reflecting the technology parameters such as supply voltage Vdd, channel length, process-induced threshold variation, and operating temperature. As an example, the framework is used to investigate the mean time to error of flip-flops built in a 32 nm fully-depleted silicon-on-insulator technology operating in the subthreshold regime subject to two limiting fluxes of alpha particle radiation: high at 100 (α/h.cm2) and ultra-low alpha (ULA) emission 0.002 (α/h.cm2).
TL;DR: In this paper, the dependence of the single event response of AlSb/InAs HEMTs on details of the doping, layer thicknesses, and contamination levels was investigated.
Abstract: We investigate the dependence of the single-event response of AlSb/InAs HEMTs on details of the doping, layer thicknesses, and contamination levels. The transconductance depends on the Δ-doping and layer thickness, which are shown to have the maximum impact on charge collection when the device is biased near the pinch-off voltage. In the on condition (near zero gate bias), the effect is minimal. The possible role of carbon contamination near the substrate-buffer heterointerface in reducing some of the longer transients is discussed.
01 Oct 2010
TL;DR: A Monte Carlo method for computing the frequency and characteristics of single event effects in microelectronic devices and with appropriate assumptions is shown to reduce to the rectangular parallelepiped (RPP) rate prediction method.
Abstract: In this paper, we describe a Monte Carlo method for computing the frequency and characteristics of single event effects in microelectronic devices. The method combines detailed physical modeling of individual radiation events, device simulations to estimate charge collection, and circuit simulations to determine the system-level effects of collected charge. A mathematical analysis of the Monte Carlo method is given, and with appropriate assumptions is shown to reduce to the rectangular parallelepiped (RPP) rate prediction method. A computer implementation of the method is described and results of a sample calculation are presented.
19 Jul 2010
TL;DR: A new Particle-Induced Single Event Latchup Mechanism Observed in a Cryogenic CMOS Readout Integrated Circuit and its implications for particle-induced single event latchup mechanism research are studied.
Abstract: • ~c:Jc::::J C3[E]C:J([J[!J ••• New Particle-Induced Single Event Latchup Mechanism Observed in a Cryogenic CMOS Readout Integrated Circuit Cheryl J. Marshall1, Paul W. Marsha112, Raymond L. Ladbury1, Augustyn Waczynski3, Roger D. Foltz1, Rajan Arora", Nathaniel A. Dodds5 , John D. Cressler", Jonathan A. Pellish\ Dakai Chen6, Duncan M. Kahle1, Gregory S. Delo3, Emily Kan1, Nicholas Boehm3, Robert A. Reed5, and Kenneth A. LaBel1
02 May 2010
TL;DR: In this paper, AlSb HEMTs stressed with hot electrons may exhibit shifts in the peak transconductance towards more negative gate voltages and are most degradation prone in operating conditions with high vertical gate field.
Abstract: InAs - AlSb HEMTs stressed with hot electrons may exhibit shifts in the peak transconductance towards more negative gate voltages. The devices are most degradation prone in operating conditions with high vertical gate field. Annealing trends and theoretical calculations indicate the possible role of an oxygen-induced metastable defect.