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Effects of total dose irradiation on single-event upset hardness

IEEE Transactions on Nuclear Science

Schwank, James R.; Shaneyfelt, Marty R.; Felix, James A.; Dodd, Paul E.; Baggio, J.; Ferlet-Cavrois, V.; Paillet, P.; Hash, Gerald L.; Flores, Richard S.; Massengill, L.W.; Blackmore, E.

The effect of total dose on SEU hardness is investigated as a function of temperature and power supply voltage to determine worst-case hardness assurance test conditions for space environments. SRAMs from six different vendors were characterized for single-event upset (SEU) hardness at proton energies from 20 to 500 MeV and at temperatures of 25 and 80°C after total dose irradiating the SRAMs with either protons, Co-60 gamma rays, or low-energy x-rays. It is shown that total dose irradiation and the memory pattern written to the memory array during total dose irradiation and SEU characterization can substantially affect SEU hardness for some SRAMs. For one SRAM, the memory pattern made more than two orders of magnitude difference in SEU cross section at the highest total dose level examined. For all SRAMs investigated, the memory pattern that led to the largest increase in SEU cross section was the same memory pattern that led to the maximum increase in total-dose induced power supply leakage current. In addition, it is shown that increasing the temperature during SEU characterization can also increase the effect of total dose on SEU hardness. As a result, worst-case SEU hardness assurance test conditions are the maximum total dose and temperature of the system environment, and the minimum operating voltage of the SRAM. Possible screens for determining whether or not the SEU cross section of an SRAM will vary with total dose, based on the magnitude of the increase in power supply leakage current with total dose or the variation in SEU cross section with power supply voltage, have been suggested. In contrast to previous works, our results using selective area x-ray irradiations show that the source of the effect of total dose on SEU hardness is radiation-induced leakage currents in the memory cells. The increase in SEU cross section with total dose appears to be consistent with radiation-induced currents originating in the memory cells affecting the output bias levels of bias level shift circuitry used to control the voltage levels to the memory cells and/or due to the lowering of the noise margin of individual memory cells caused by radiation-induced leakage currents. © 2006 IEEE.

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Elimination of enhanced low-dose-rate sensitivity in linear bipolar devices using silicon-carbide passivation

IEEE Transactions on Nuclear Science

Shaneyfelt, Marty R.; Maher, Michael C.; Camilletti, Robert C.; Schwank, James R.; Pease, Ronald L.; Russell, Brian A.; Dodd, Paul E.

The type of final chip passivation layer used to fabricate linear bipolar circuits can have a major impact on the total dose hardness of some circuits. It is demonstrated that National Semiconductor Corporation linear bipolar devices fabricated with only an amorphous silicon carbide passivation layer do not exhibit enhanced low-dose-rate sensitivity (ELDRS), while devices from the same production lot fabricated with other types of passivation layers are ELDRS sensitive. SiC passivation possesses mechanical, electrical and chemical properties that make it compatible with linear device fabrication processes. These properties of SiC passivation layers, combined with the excellent radiation response of devices passivated with SiC, make SiC passivation layers a very attractive choice for devices packaged in either ceramic or plastic-encapsulated packages for use in space environments. © 2006 IEEE.

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Effects of particle energy on proton-induced single-event latchup

IEEE Transactions on Nuclear Science

Schwank, James R.; Shaneyfelt, Marty R.; Baggio, J.; Dodd, Paul E.; Felix, James A.; Ferlet-Cavrois, V.; Paillet, P.; Lambert, D.; Sexton, Frederick W.; Hash, Gerald L.; Blackmore, E.

The effect of proton energy on single-event latchup (SEL) in present-day SRAMs is investigated over a wide range of proton energies and temperature. SRAMs from five different vendors were irradiated at proton energies from 20 to 500 MeV and at temperatures of 25° and 85°C. For the SRAMs and radiation conditions examined in this work, proton energy SEL thresholds varied from as low as 20 MeV to as high as 490 MeV. To gain insight into the observed effects, the heavy-ion SEL linear energy transfer (LET) thresholds of the SRAMs were measured and compared to high-energy transport calculations of proton interactions with different materials. For some SRAMs that showed proton-induced SEL, the heavy-ion SEL threshold LET was as high as 25 MeV-cm 2/mg. Proton interactions with Si cannot generate nuclear recoils with LETs this large. Our nuclear scattering calculations suggest that the nuclear recoils are generated by proton interactions with tungsten. Tungsten plugs are commonly used in most high-density ICs fabricated today, including SRAMs. These results demonstrate that for system applications where latchups cannot be tolerated, SEL hardness assurance testing should be performed at a proton energy at least as high as the highest proton energy present in the system environment. Moreover, the best procedure to ensure that ICs will be latchup free in proton environments may be to use a heavy-ion source with LETs ≥40 MeV-cm 2/mg. © 2005 IEEE.

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Radiation-induced off-state leakage current in commercial power MOSFETs

Proposed for publication in the IEEE Transactions on Nuclear Science.

Felix, James A.; Shaneyfelt, Marty R.; Dodd, Paul E.; Draper, Bruce L.; Schwank, James R.; Dalton, Scott D.

The total dose hardness of several commercial power MOSFET technologies is examined. After exposure to 20 krad(SiO{sub 2}) most of the n- and p-channel devices examined in this work show substantial (2 to 6 orders of magnitude) increases in off-state leakage current. For the n-channel devices, the increase in radiation-induced leakage current follows standard behavior for moderately thick gate oxides, i.e., the increase in leakage current is dominated by large negative threshold voltage shifts, which cause the transistor to be partially on even when no bias is applied to the gate electrode. N-channel devices biased during irradiation show a significantly larger leakage current increase than grounded devices. The increase in leakage current for the p-channel devices, however, was unexpected. For the p-channel devices, it is shown using electrical characterization and simulation that the radiation-induced leakage current increase is related to an increase in the reverse bias leakage characteristics of the gated diode which is formed by the drain epitaxial layer and the body. This mechanism does not significantly contribute to radiation-induced leakage current in typical p-channel MOS transistors. The p-channel leakage current increase is nearly identical for both biased and grounded irradiations and therefore has serious implications for long duration missions since even devices which are usually powered off could show significant degradation and potentially fail.

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Arsenic ion implant energy effects on CMOS gate oxide hardness

Proposed for publication in the IEEE Transactions on Nuclear Science.

Draper, Bruce L.; Shaneyfelt, Marty R.; Young, Ralph W.; Headley, Thomas J.; Dondero, Richard D.

Under conditions that were predicted as 'safe' by well-established TCAD packages, radiation hardness can still be significantly degraded by a few lucky arsenic ions reaching the gate oxide during self-aligned CMOS source/drain ion implantation. The most likely explanation is that both oxide traps and interface traps are created when ions penetrate and damage the gate oxide after channeling or traveling along polysilicon grain boundaries during the implantation process.

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Direct measurement of transient pulses induced by laser and heavy ion irradiation in deca-nanometer devices

Proposed for publication in the IEEE Transactions on Nuclear Science.

Schwank, James R.; Shaneyfelt, Marty R.

This paper investigates the transient response of 50-nm gate length fully and partially depleted SOI and bulk devices to pulsed laser and heavy ion microbeam irradiations. The measured transient signals on 50-nm fully depleted devices are very short, and the collected charge is small compared to older 0.25-{micro}m generation SOI and bulk devices. We analyze in detail the influence of the SOI architecture (fully or partially depleted) on the pulse duration and the amount of bipolar amplification. For bulk devices, the doping engineering is shown to have large effects on the duration of the transient signals and on the charge collection efficiency.

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Identification of radiation-induced parasitic leakage paths using light emission microscopy

IEEE Transactions on Nuclear Science

Shaneyfelt, Marty R.; Tangyunyong, Paiboon T.; Hill, Thomas A.; Soden, Jerry M.; Flores, Richard S.; Schwank, James R.; Dodd, Paul E.; Hash, Gerald L.

Eliminating radiation-induced parasitic leakage paths in integrated circuits (ICs) is key to improving their total dose hardness. Semiconductor manufacturers can use a combination of design and/or process techniques to eliminate known radiation-induced parasitic leakage paths. However, unknown or critical radiation-induced parasitic leakage may still exist on fully processed ICs and it is extremely difficult (if not impossible) to identify these leakage paths based on radiation induced parametric degradation. We show that light emission microscopy can be used to identify the location of radiation-induced parasitic leakage paths in ICs. This is illustrated by using light emission microscopy to find radiation-induced parasitic leakage paths in partially-depleted silicon on insulator static random-access memories (SRAMs). Once leakage paths were identified, modifications were made to the SRAM design to improve the total dose radiation hardness of the SRAMs. Light emission microscopy should prove to be an important tool for the development of future radiation hardened technologies and devices.

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Radiation effects microscopy for failure analysis of microelectronic devices

Doyle, Barney L.; Dodd, Paul E.; Shaneyfelt, Marty R.; Schwank, James R.

Microelectronic devices in satellites and spacecraft are exposed to high energy cosmic radiation. Furthermore, Earth-based electronics can be affected by terrestrial radiation. The radiation causes a variety of Single Event Effects (SEE) that can lead to failure of the devices. High energy heavy ion beams are being used to simulate both the cosmic and terrestrial radiation to study radiation effects and to ensure the reliability of electronic devices. Broad beam experiments can provide a measure of the radiation hardness of a device (SEE cross section) but they are unable to pinpoint the failing components in the circuit. A nuclear microbeam is an ideal tool to map SEE on a microscopic scale and find the circuit elements (transistors, capacitors, etc.) that are responsible for the failure of the device. In this paper a review of the latest radiation effects microscopy (REM) work at Sandia will be given. Different SEE mechanisms (Single Event Upset, Single Event Transient, etc.) and the methods to study them (Ion Beam Induced Charge (IBIC), Single Event Upset mapping, etc.) will be discussed. Several examples of using REM to study the basic effects of radiation in electronic devices and failure analysis of integrated circuits will be given.

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Results 76–100 of 127
Results 76–100 of 127