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ABSTRACT: Pulse widths of single-event transients produced by alpha particles in a 65-nm bulk CMOS technology are reported. The experimental setup and calibration of the alpha particle experiment is described in detail. A focused-ion beam is also utilized to explore how pulse broadening in the test circuit impacts the alpha particle SET measurements. The results of this work show that alpha particles are able to induce transient signals with a width of about 25 ps in this technology.
IEEE Transactions on Nuclear Science 07/2011; · 1.45 Impact Factor
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J.R. Schwank,
M.R. Shaneyfelt,
P.E. Dodd,
D. McMorrow, G. Vizkelethy,
V. Ferlet-Cavrois,
P.M. Gouker,
R.S. Flores,
J. Stevens,
S.B. Buchner,
S.M. Dalton,
S.E. Swanson
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ABSTRACT: The amounts of charge collection by single-photon absorption (SPA) and by two-photon absorption (TPA) laser testing techniques have been directly compared using specially made SOI diodes. For SPA measurements and some TPA measurements, the back substrates of the diodes were removed by etching with XeF<sub>2</sub>. With the back substrates removed, the amount of TPA induced charge collection can be correlated to the amount of SPA induced charge collection. There are significant differences, however, in the amount of TPA induced charge collection for diodes with and without substrates. For the SOI diodes of this study, this difference appears to arise from several contributions, including nonlinear-optical losses and distortions that occur as the pulse propagates through the substrate, as well as displacement currents that occur only when the back substrate is present. These results illustrate the complexity of interpreting TPA and SPA single-event upset measurements.
IEEE Transactions on Nuclear Science 07/2011; · 1.45 Impact Factor
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ABSTRACT: The development of a new radiation effects microscopy (REM) technique is crucial as emerging semiconductor technologies demonstrate smaller feature sizes and thicker back end of line (BEOL) layers. To penetrate these materials and still deposit sufficient energy into the device to induce single event effects, high energy heavy ions are required. Ion photon emission microscopy (IPEM) is a technique that utilizes coincident photons, which are emitted from the location of each ion impact to map out regions of radiation sensitivity in integrated circuits and devices, circumventing the obstacle of focusing high-energy heavy ions. Several versions of the IPEM have been developed and implemented at Sandia National Laboratories (SNL). One such instrument has been utilized on the microbeam line of the 6 MV tandem accelerator at SNL. Another IPEM was designed for ex-vacu use at the 88'' cyclotron at Lawrence Berkeley National Laboratory (LBNL). Extensive engineering is involved in the development of these IPEM systems, including resolving issues with electronics, event timing, optics, phosphor selection, and mechanics. The various versions of the IPEM and the obstacles, as well as benefits associated with each will be presented. In addition, the current stage of IPEM development as a user instrument will be discussed in the context of recent results.
AIP Conference Proceedings 05/2011; 1336(1).
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ABSTRACT: We report on the design and measured results of a new SiGe HBT radiation hardening by design technique called the “inverse-mode cascode” (IMC). A third-generation SiGe HBT IMC device was tested in a time resolved ion beam induced charge collection (TRIBICC) system, and was found to have over a 75% reduction in peak current transients with the use of an n-Tiedown on the IMC sub-collector node. Digital shift registers in a 1st-generation SiGe HBT technology were designed and measured under a heavy-ion beam, and shown to increase the LET threshold over standard npn only shift registers. Using the CREME96 tool, the expected orbital bit-errors/day were simulated to be approximately 70% lower with the IMC shift register. These measured results help demonstrate the efficacy of using the IMC device as a low-cost means for improving the SEE radiation hardness of SiGe HBT technology without increasing area or power.
IEEE Transactions on Nuclear Science 01/2011; · 1.45 Impact Factor
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E.P. Wilcox,
S.D. Phillips,
Peng Cheng,
T. Thrivikraman,
A. Madan,
J.D. Cressler, G. Vizkelethy,
P.W. Marshall,
C. Marshall,
J.A. Babcock,
K. Kruckmeyer,
R. Eddy,
G. Cestra,
Benyong Zhang
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ABSTRACT: We report heavy-ion microbeam and total dose data for a new complementary (npn + pnp) SiGe on thick-film SOI technology. Measured transient waveforms from heavy-ion strikes indicate a significantly shortened single-event-induced transient current, while maintaining the total dose robustness associated with SiGe devices. Heavy-ion broad-beam data confirm a reduced single event upset (SEU) cross-section in a high-speed shift register circuit.
IEEE Transactions on Nuclear Science 01/2011; · 1.45 Impact Factor
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ABSTRACT: We investigate the efficacy of mitigating radiation-based single event effects (SEE) within circuits incorporating SiGe heterojunction bipolar transistors (HBTs) built with an N-Ring, a transistor-level layout-based radiation hardened by design (RHBD) technique. Previous work of single-device ion-beam induced charge collection (IBICC) studies has demonstrated significant reductions in peak collector charge collection and sensitive area for charge collection; however, few circuit studies using this technique have been performed. Transient studies performed with Sandia National Laboratory's (SNL) 36 MeV <sup>16</sup>O microbeam on voltage references built with N-Ring SiGe HBTs have shown mixed results, with reductions in the number of large voltage disruptions in addition to new sensitive areas of low-level output voltage disturbances. Similar discrepancies between device-level IBICC results and circuit measurements are found for the case of digital shift registers implemented with N-Ring SiGe HBTs irradiated in a broadbeam environment at Texas A&M's Cyclotron Institute. The error cross-section curve of the N-Ring based register is found to be larger at larger ion LETs than the standard SiGe register, which is clearly counter-intuitive. We have worked to resolve the discrepancy between the measured circuit results and the device-level IBICC measurements, by re-measuring single-device N-Ring SiGe HBTs using a time-resolved ion beam induced charge (TRIBIC) set-up that allows direct capture of nodal transients. Coupling these measurements with full 3-D TCAD simulations provides complete insight into the origin of transient currents in an N-Ring SiGe HBT. The detailed structure of these transients and their bias dependencies are discussed, together with the ramifications for the design of space-borne analog and digital circuits using SiGe HBTs.
IEEE Transactions on Nuclear Science 01/2011; · 1.45 Impact Factor
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K.A. Moen,
S.D. Phillips,
E.P. Wilcox,
J.D. Cressler,
H. Nayfeh,
A.K. Sutton,
J.H. Warner,
S.P. Buchner,
D. McMorrow, G. Vizkelethy,
P. Dodd
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ABSTRACT: We investigate the single-event transient (SET) response of T-body and notched-body contacted MOSFETs from a commercial 45 nm SOI RF-CMOS technology. Although body-contacted devices suffer from reduced RF performance compared to floating body devices, previous work on 65 nm and 90 nm MOSFETs has shown that the presence of a body-contact significantly mitigates the total ionizing dose (TID) sensitivity that is exhibited in floating-body SOI MOSFETs. The influence of body-contacting schemes on the single-event effect (SEE) sensitivity is examined here through time-resolved measurements of laser and microbeam-induced transients from T-body and notched-body MOSFETs. Laser-induced transients demonstrate the reduced SEE sensitivity of the notched-body MOSFETs as compared to the T-body MOSFETs; this is evidenced by a uniform reduction in the peak transient magnitudes and collected charge for transients captured at the worst-case bias of V<sub>DS</sub> = 1.0 V, as well as with all terminals grounded. Microbeam-induced transient data are also presented to support the validity of the laser-induced transient data. Together, these data provide new insight into the RF versus TID versus SEE tradeoffs associated with body contacting schemes in nm-scale MOSFETs, an important concern for emerging space-based electronics applications.
IEEE Transactions on Nuclear Science 01/2011; · 1.45 Impact Factor
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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.
IEEE Transactions on Nuclear Science 01/2011; · 1.45 Impact Factor
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ABSTRACT: We have explored defect annealing in radiation damaged silicon in a regime characterized by defect clusters and higher doping. Several types of pnp and npn Si bipolar transistors have been irradiated with ions and neutrons, then isochronally annealed from 300 to 600 K to study the evolution of deep level transient spectroscopy (DLTS) defect signatures. Variations in these data with radiation environment, Fermi level, annealing temperature, and doping density have been used to separate the contributions of three dominant defects to the DLTS defect spectra. We find that the normal Si divacancy and a divacancylike defect with similar properties make similar contributions to a DLTS peak normally associated with transitions from the single minus charge state of the divacancy. However the latter defect is clearly associated with the presence of defect clusters. The vacancy-donor center can also contribute to this high temperature DLTS signature, and its relative importance can be quantitatively assessed by varying doping density and the bias applied to the sample p/n junctions during annealing, and also by the observation that another, donor-related defect grows in as this center anneals. The ratio of vacancy-donor and vacancy-oxygen pairs appears to accurately follow that seen in earlier studies of gamma-irradiated Si. Discussions are presented concerning the effects of defect clustering on the structure, appearance, and evolution of the defects we have identified.
Journal of Applied Physics 04/2010; · 2.17 Impact Factor
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ABSTRACT: We investigate, for the first time, the potential for SEE mitigation of a newly-developed device architecture in a 3rd generation high-speed SiGe platform. This new device architecture is termed the ¿inverse-mode cascode SiGe HBT¿ and is comprised of two standard devices sharing a buried subcollector and operated in a cascode configuration. Verification of the TID immunity is demonstrated using 10 keV X-rays, while an investigation of the SEE susceptibility is performed using a 36 MeV <sup>16</sup>O ion. IBICC results show strong sensitivities to device bias with only marginal improvement when compared to a standard device; however, by providing a conductive path from the buried subcollector (C-Tap) to a voltage potential, almost all collected charge is induced on the C-Tap terminal instead of the collector terminal. These results are confirmed using full 3-D TCAD simulations which also provides insight into the physics of this new RHBD device architecture. The implications of biasing the C-Tap terminal in a circuit context are also addressed.
IEEE Transactions on Nuclear Science 01/2010; · 1.45 Impact Factor
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P.E. Dodd,
M.R. Shaneyfelt,
B.L. Draper,
R.W. Young,
D. Savignon,
J.B. Witcher, G. Vizkelethy,
J.R. Schwanki,
Z.J. Shen,
P. Shea,
M. Landowski,
S.M. Dalton
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ABSTRACT: The radiation response of lateral power MOSFETs in total dose and energetic particle environments is explored. Results indicate that lateral power MOSFETs can be quite susceptible to single-event burnout. Tradeoffs involved in developing radiation hardened lateral power MOSFETs for point-of-load applications are studied using experiments and device simulations. Both design and fabrication process techniques can be used to significantly improve the single-event effect performance of lateral power MOSFETs, but the trade space between electrical and radiation performance must be carefully considered to produce an optimized design for point-of-load applications.
IEEE Transactions on Nuclear Science 01/2010; · 1.45 Impact Factor
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R.M. Diestelhorst,
S.D. Phillips,
A. Appaswamy,
A.K. Sutton,
J.D. Cressler,
J.A. Pellish,
R.A. Reed, G. Vizkelethy,
P.W. Marshall,
H. Gustat,
B. Heinemann,
G.G. Fischer,
D. Knoll,
B. Tillack
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ABSTRACT: We investigate a novel implementation of junction isolation to harden a 200 GHz SiGe:C HBT technology without deep trench isolation against single event effects. The inclusion of isolation is shown to have no effect on the dc or ac performance of the nominal device, and likewise does not reduce the HBTs inherent tolerance to TID radiation exposure on the order of a Mrad. A 69% reduction in total integrated charge collection across a slice through the center of the device was achieved. In addition, a 26% reduction in collected charge is reported for strikes to the center of the emitter. 3-D NanoTCAD simulations are performed on RHBD and control device models yielding a good match to measured results for strikes from the emitter center to 8 ¿m away. This result represents one of the most effective transistor layout-level RHBD approaches demonstrated to date in SiGe.
IEEE Transactions on Nuclear Science 01/2010; · 1.45 Impact Factor
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N.A. Dodds,
R.A. Reed,
M.H. Mendenhall,
R.A. Weller,
M.A. Clemens,
P.E. Dodd,
M.R. Shaneyfelt, G. Vizkelethy,
J.R. Schwank,
V. Ferlet-Cavrois,
J.H. Adams,
R.D. Schrimpf,
M.P. King
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ABSTRACT: Direct charge collection measurements are presented, which prove that the presence of tungsten near sensitive volumes leads to extreme charge collection events through nuclear reactions. We demonstrate that, for a fixed incident particle linear energy transfer (LET), increasing particle energy beyond a certain point causes a decrease in nuclear reaction-induced charge collection. This suggests that a worst-case energy exists for single-event effect (SEE) susceptibility, which depends on the technology, device layout, and the incident ions' fixed LET value. A Monte Carlo approach for identifying the worst-case energy is applied to certain bulk-Si and silicon-on-insulator (SOI) technologies. Simulation results suggest that the decrease in charge collection beyond the worst-case energy occurs because the secondary particles produced from the high-energy nuclear reactions have less mass and higher energy and are therefore less ionizing than those produced by lower-energy reactions.
IEEE Transactions on Nuclear Science 01/2010; · 1.45 Impact Factor
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J.A. Pellish,
R.A. Reed,
D. McMorrow, G. Vizkelethy,
V.F. Cavrois,
J. Baggio,
P. Paillet,
O. Duhamel,
K.A. Moen,
S.D. Phillips,
R.M. Diestelhorst,
J.D. Cressler,
A.K. Sutton,
A. Raman,
M. Turowski,
P.E. Dodd,
M.L. Alles,
R.D. Schrimpf,
P.W. Marshall,
K.A. LaBel
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ABSTRACT: Silicon-germanium heterojunction bipolar transistor (SiGe HBT) heavy ion-induced current transients are measured using Sandia National Laboratories' microbeam and high- and low-energy broadbeam sources at the Grand Acce¿le¿rateur National d'Ions Lourds, Caen, France, and the University of Jyva¿skyla¿, Finland. The data were captured using a custom broadband IC package and real-time digital phosphor oscilloscopes with at least 16 GHz of analog bandwidth. These data provide detailed insight into the effects of ion strike location, range, and LET.
IEEE Transactions on Nuclear Science 01/2010; · 1.45 Impact Factor
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L. Najafizadeh,
S.D. Phillips,
K.A. Moen,
R.M. Diestelhorst,
M. Bellini,
P.K. Saha,
J.D. Cressler, G. Vizkelethy,
M. Turowski,
A. Raman,
P.W. Marshall
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ABSTRACT: We investigate the single-event transient (SET) response of bandgap voltage references (BGRs) implemented in SiGe BiCMOS technology through heavy ion microbeam experiments. The SiGe BGR circuit is used to provide the input reference voltage to a voltage regulator. SiGe HBTs in the BGR circuit are struck with 36-MeV oxygen ions, and the subsequent transient responses are captured at the output of the regulator. Sensitive devices responsible for generating transients with large peak magnitudes (more than 5% of the dc output voltage) are identified. To determine the effectiveness of a transistor-layout-based radiation hardened by design (RHBD) technique with respect to immunity to SETs at the circuit level, the BGR circuit implemented with HBTs surrounded by an alternate reverse-biased pn junction (n-ring RHBD) is also bombarded with oxygen ions, and subsequent SETs are captured. Experimental results indicate that the number of events causing transients with peak magnitude more than 5% above the dc level have been reduced in the RHBD version; however, with the inclusion of the n-ring RHBD, new locations for the occurrence of transients (albeit with smaller peak magnitude) are created. Transients at the transistor-level are also independently captured and are presented. It is demonstrated that while the transients are short at the transistor level (ns duration), relatively long transients are obtained at the circuit level (hundreds of nanoseconds). In addition, the impact of the SET response of the BGR on the performance of an ultra-high-speed 3-bit SiGe analog-to-digital converter (ADC) is investigated through simulation. It is shown that ion-induced transients in the reference voltage could eventually lead to data corruption at the output of the ADC.
IEEE Transactions on Nuclear Science 01/2010; · 1.45 Impact Factor
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S.D. Phillips,
A.K. Sutton,
A. Appaswamy,
M. Bellini,
J.D. Cressler,
A. Grillo, G. Vizkelethy,
P. Dodd,
M. McCurdy,
R. Reed,
P. Marshall
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ABSTRACT: We investigate, for the first time, the impact of deep trench isolation on the total ionizing dose (TID) and single event upset (SEU) tolerance of advanced SiGe HBTs. We employ a combination of 63 MeV protons, 10 keV X-rays, and 36 MeV oxygen ion microbeam irradiation and compare a 3<sup>rd</sup> generation, high-performance (HP), deep-trench isolated, SiGe BiCMOS platform with its cost-performance (CP) variant without deep-trenches. Although the CP SiGe HBTs are shown to be more susceptible to TID damage, the elevated damage is not attributed to variations in deep trench isolation (DTI), but to spacer oxide differences. CP SiGe HBTs are surprisingly found to offer a potential built-in self-mitigation mechanism for SEU, which is a direct result of the influence of the deep trench isolation on the charge collection dynamics associated with ion strikes. Calibrated, full 3D ion strike TCAD simulations are employed to explain the results, revealing substantial enhancement of radial charge diffusion for structures implemented with little to no deep trench. Mitigation of charge collection events are found to occur for emitter-center strikes for devices with limited/eliminated DTI with the caveat of larger collection for outside-DTI ion strikes.
Reliability Physics Symposium, 2009 IEEE International; 05/2009
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ABSTRACT: We report on an early-time inverse gain comparison between ion and neutron irradiated silicon bipolar junction transistors. We find ion irradiations to be an excellent simulator for fast-burst neutrons for early-time behavior and damage creation rates. In addition we report on an experimental to simulation comparison of transient gain annealing response. The simulations are from a physics based modeling approach that is being developed at Sandia National Laboratories as part of the Qualification Alternatives to the Sandia Pulsed Reactor (QASPR) Program. We find excellent agreement between simulation and experiment across a wide range of irradiation conditions.
IEEE Transactions on Nuclear Science 01/2009; · 1.45 Impact Factor
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ABSTRACT: We present the first charge loss model of heavy ion induced radiation damage on nanocrystal memory cells. The model takes into account the nanocrystal distribution non uniformity and the effect of different programming techniques, which may produce non uniform charging of the nanocrystals. The model has been validated with a focused microbeam test. It provides an estimation of both the ion track size and the average number of ion hits required for achieving a given charge loss. In our irradiation experiments we estimated an ion track size (diameter) of 85 nm for 50-MeV Cu ions. This model confirms also the good robustness of nanocrystal memories against heavy ion irradiation and their much stronger tolerance than the conventional floating gate based memories.
IEEE Transactions on Nuclear Science 01/2009; · 1.45 Impact Factor
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ABSTRACT: We study proton and heavy ion irradiation effects on phase change memories (PCM) with MOSFET and BJT selectors and the effect of the irradiation on the retention characteristics of these devices. Proton irradiation produces noticeable variations in the cell distributions in PCM with MOSFET selectors mostly due to leakage currents affecting the transistors. PCM with BJT selectors show only small variations after proton irradiation. PCM cells do not appear to be impacted by heavy-ion irradiation. Using high temperature accelerated retention tests, we demonstrate that the retention capability of these memories is not compromised by the irradiation.
IEEE Transactions on Nuclear Science 01/2009; · 1.45 Impact Factor
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E.J. Montes,
R.A. Reed,
J.A. Pellish,
M.L. Alles,
R.D. Schrimpf,
R.A. Weller,
M. Varadharajaperumal,
G. Niu,
A.K. Sutton,
R. Diestelhorst,
G. Espinel,
R. Krithivasan,
J.P. Comeau,
J.D. Cressler,
P.W. Marshall, G. Vizkelethy
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ABSTRACT: Microbeam measurements and TCAD simulations are used to examine the effects of ion angle of incidence on the charge collected from events occurring in a Silicon Germanium (SiGe) Heterojunction Bipolar Transistor (HBT). The results identify the geometrically driven charge-collection mechanisms that dominate the low LET broad beam SEU response. The deep trench isolation that surrounds the transistor significantly modulates the charge transport and, therefore, the charge collected by the collector. A new way of estimating critical charge, , for upset in SiGe HBT circuits is proposed based on TCAD simulation results and measured broadbeam data.
IEEE Transactions on Nuclear Science 07/2008; · 1.45 Impact Factor
