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Abstract-- We have applied a 30keV focused ion beam (FIB) as adiagnostic tool for isolating and probing packaged-part devicesfor the extraction of analog single-event-transient (ASET)model parameters. Complete ASET circuit modeling of theOP27 high-speed, low-noise operational amplifier andcomparisons to laser and broad-beam experiments arepresented.

I. INTRODUCTION

IRCUIT simulation has become an important tool in thestudy of analog single event transients (ASETs). Due to

time and cost issues, simulations represent a powerfuldiagnostic and prediction methodology that can supportempirical testing, such as heavy-ion characterization.Simulations give the user the ability to examine unlimited testconditions and circuit applications. The key to accurate andinsightful simulation results is a set of detailed transistor levelmodels. To create these models, one must have an in-depthknowledge of the individual transistors used in the part underinvestigation. In today’s market, most manufacturers arereluctant to release details on their technology or processingrecipe. Without this information or on-chip test patternsrepresenting the individual transistors used in the process,researchers studying the effects of space-based radiationmust have a way to extract transistor level SPICE models.

Manuscript received September 15, 2003. This work was supported

in part by the Defense Threat Reduction Agency under contractnumber DTRA01-00-C-001

J. D. Rowe, L. W. Massengill, Y. Boulghassoul, A. L. Sternberg, andR. A. Weller are with Vanderbilt University Department of ElectricalEngineering and Computer Science, Nashville TN 37235 USA(telephone: 615-343-6704 emails: jason.d.rowe@vanderbilt.edu,lloyd.massengill@vanderbilt.edu, younes.boulghassoul@vanderbilt.edu,andrew.l.sternberg@vanderbilt.edu, robert.a.weller@vanderbilt.edu)

S. Buchner is with QSS Group Inc., Seabrook MD 20706 USA(telephone: 301-286-5019, email: sbuchner@pop500.gsfc.nasa.gov)

D. McMorrow is with NRL, Washington DC 20375 USA (telephone:202-767-5469, email: mcmorrow@ccs.nrl.navy.mil)

M. Savage is with NAVSEA, Crane IN 47522 USA (telephone: 812-854-6927, email: savage_m@atd.crane.navy.mil)

The Focused Ion Beam (FIB) is a tool that can be used inthe process of extracting these detailed models. The FIB canbe used to isolate individual transistors, resistors andcapacitors from a functioning packaged part. It also has theability to mill/etch away the surface passivation layer toexpose metal interconnect for precision probing withmicromanipulators. This offers a method for measuringindividual transistor characteristics from devices in whichlittle information is known. Combining this method withextraction and optimization tools, accurate transistor SPICEmodels can be created.

In this paper, the FIB is used as a tool to aid in theextraction of a detailed transistor level circuit model for theOP27, a high-speed, low-noise bipolar precision DCoperational amplifier manufactured by Analog Devices. Thisop amp is a prime candidate for space applications and NASAdeployment interests. Due to the vulnerability of linearbipolar circuits in radiation environments, the sensitivity toheavy ions must be investigated. ASET circuit simulationswill be used to examine the mechanisms responsible for SETs,and allow multiple biasing and operating conditions to beexplored as previously shown [1]-[3].

We present the setup, operation, techniques, andlimitations involved in performing the necessary steps towardextracting accurate ASET transistor models from functionallyintegrated circuitry. The necessary characterization curvesand important parameters for bipolar transistors are presented.The methods used to extract detailed models are implementedon the OP27, and the ASET sensitivity of that part is explored.Similar methods as used with the widely integratedoperational amplifier LM124 will be used for the validation ofthe model [4]. Model validation is first shown by comparingtypical performance characteristics as seen in the data sheetprovided by the manufacturer. These curves show that thefunctionality and performance of the modeled circuit iscomparable to the actual circuit for dc and frequencyresponses. The internal ASET behavior of the modeled OP27is examined by the use of experimental and simulation tools.Simulation results are supported by laser experiments to verifythe accuracy of the models for transient SET analysis. Themodel is also validated by comparing the computer

Focused-Ion-Beam Assisted Bipolar TransistorCharacterization and Analog Single-Event-

Transient Circuit Analysis of the OP27

J. D. Rowe, Student Member, IEEE, L. W. Massengill, Senior Member, IEEE, Y. BoulghassoulStudent Member, IEEE, A. L. Sternberg Student Member, IEEE, R. A. Weller, Member, IEEE, S.

Buchner, Member, IEEE, D. McMorrow, Member, IEEE, and M. W. Savage, Member, IEEE

C

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simulations to broad-beam data taken with different biasconditions and circuit configurations as that of the laser.

II. FOCUSED ION BEAM

The FIB system used in this work is the 200xP manufacturedby FEI/Philips. It is a user-friendly system that utilizes avacuum ion chamber, navigation video monitor, intensityspecific signal channel-tron, photo quality hard copy output,and a control computer. There are various beam current andmagnification levels ranging from 1pA-11500pA, and 250x-5000x respectively. The FIB uses a fine beam of gallium ionsthat scan over the surface of the part. At higher beamcurrents the gallium beam rapidly sputters away the surfaceallowing the removal of material. If the beam current isreduced, the secondary electrons emitted from the partssurface can be detected and used to form high-resolutionimages. Due to its abilities, the FIB is widely used in theexamination of materials such as semiconductors, solar cells,and thin films, and for integrated circuit cross-sectioning,design modification and failure analysis [5].

The FIB is generally used for wafer level applications, butwe were able to place packaged parts inside the chamber formodification. The first step for the process was to verify thedepth of the protective passivation layer and the thickness ofthe metal circuitry throughout the part. This wasaccomplished by creating small cross-sections of the metallines at various points throughout the circuit. Using the FIB,the chosen areas were etched away revealing the layeredstructure of the passivation and metal. The part was thenrotated 45 degrees to examine the layered structure and extractthe approximate thicknesses. Once this was complete severaltransistors of each type (Vertical NPN, Lateral PNP, andSubstrate PNP) were chosen to be isolated. The transistor inquestion was located and the metal lines for the base,collector and emitter were traced out. Isolation was completedby milling approximately 5µm into the surface severing allconnections to the surrounding circuitry. The next step wasto create areas on the metal lines to make electrical contact.The passivation layer was etched away until the underlyingmetal was exposed. This took precise judgment to insure themetal be fully exposed, but not totally etching all the waythrough to the underlying silicon. Fig. 1a-c shows high-resolution images of each step of the process starting withcross sectioning, isolation, and contact pads. The sameisolation and contact pad process was performed on theresistors and capacitors included in the part to allow thecharacteristics to be extracted.

While this method produces acceptable results, it doeshave limitations, including radiation damage, timeconsumption and availability of transistors. The mostsignificant is the possibility of radiation damage due to theions entering the semiconductor material [6]. Most milling forthis method occurs at the highest current setting (11500pA),which introduces the greatest risk of damage. Due to the risk,scans at higher beam currents were limited, and imaging wasonly performed at lower current settings. All isolation cutsand contact pads were milled outside the active diffusion

regions. To diagnose the possibility of damage due to thebeam, a similar bipolar part was used to perform damage tests.A series of extreme overexposure situations were applied andthe input base current was measured after each situation. Theresults showed that even after the non-realistic situations theinput base current only varied by a maximum of 10 percentfrom the original measured value. With this small of avariation, we were confident that our techniques caused muchless damage and allowed accurate measurements to be taken.

Exposure time must also be considered since it is directlyproportional to the area and depth of each pattern. Toincrease accuracy of the models several transistors for eachtype were tested which required many patterns to be milled.Each pattern had a varying time with isolation cuts rangingfrom 5 to 20 minutes, and pad etching ranging from 3 to 10minutes. The time issue was drastically reduced as theexperience of the user increased. Becoming more familiar withthe equipment allowed multiple areas to be isolated in a singlepattern run. On the other hand, contact pad areas wereetched individually to assure proper depth, which requiredmore diagnostic time. As the accuracy of etching the padsimproved, less were required to insure proper conductivity.

To extract representative models for the process, averagesized transistors were chosen. The location and layout ofthese transistors were crucial. Transistors that sharedcommon diffusions were not used for extraction due to thepossibility of added parasitic effects. Each chosen transistorhad adequate metal line area and placement to allow goodelectrical contact without added resistance or capacitance. Toisolate all the needed transistors, multiple packaged partswere used. Isolating one transistor caused damage to one ormore surrounding devices due to the depth of the cuts. Byusing multiple parts all questionable areas were able to beexplored, and the same device could be measured in more thanpart.

Fig. 1a. Cross-sectioned area of metal line revealing the layeredstructure of the passivation layer, metal line, and underlying silicon.This step was key to evaluating depth of the isolation cuts, and contactpad areas.

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Fig. 1b. 5µm etch of a single metal line, isolating it from thesurrounding circuitry. This was performed on all connections to thetransistor, resistor, or capacitor under investigation to assure properisolation.

Fig. 1c. Contact area milled through passivation layer contactingthe underlying metal line. The bright area in the center is the metal,which was contacted with precision probe tips. As seen from the scaleit is approximately 8µm x 8µm.

III. MODEL EXTRACTION

A. Curve Extraction

The final result of the FIB is a device that is isolated fromthe package with various contact pads exposing the metalcircuitry. To continue the model extraction process, variouscharacterization curves were taken. Due to the limited widthof the metal lines the available probe area was usually lessthan 10µm x 10µm. Good electrical contact was achieved withhigh quality tungsten tips guided by precisionmicromanipulators. Once electrical contact was achieved, thecharacterization curves were acquired through a computercontrolled HP4156 parameter analyzer and HP4284 LCR meter.

Bipolar transistor models found in most SPICE applicationsutilize the Gummel-Poon and Ebers-Moll models. Since theGummel-Poon model is more accurate and complex over alloperating regions it was chosen as the basis for the curveextraction. A total of 4 curves were extracted for each deviceincluding forward Gummel (IC, IB, vs. VBE), IC vs. VCE, reverse

Gummel (IE, -IB, vs. VBC), and IE vs. VEC. From the Gummelcurves the Beta (forward and reverse gain) curves wereextracted by standard methods (IC/IB). Characterization curvesfor a representative size bipolar vertical NPN transistorlocated throughout the circuit in the OP27 are shown in Fig.2a-d. The forward characteristics allow the extraction ofparameters such as IS, BF, NF, VAF, IKF and the reversecharacteristics add the parameters BR, NR, VAR, IKR. Thesaturation condition parameters are also extracted (ISE, NE, ISC,NC), along with the nodal resistances (RE, RB, RBM, and RC).Another set of important parameters for proper SET modelsare the junction capacitances (CJ, MJ, VJ), which are extractedfrom C-V sweeps of each active junction. A representativejunction capacitance curve for the vertical NPN can be seen inFig. 2e. Once optimized, all these parameters combined createan accurate transistor level SPICE model that can be used incomputer simulations.

B. Parameter Optimization

Characteristic Gummel-Poon curves describe how a singletransistor functions over a range of current and voltage steps.This data must then be transformed into SPICE parametersthat will reproduce the characteristics in a computersimulation. We used a two-step method to translate the datainto the needed parameters. In the initial step an in-housecomputer routine, using the optimization abilities of theDAKOTA toolkit, with a built in SPICE loop was used [7]. Theprogram generated all needed parameters within a specifiedrange and used internal least-squares curve-fitting methods tooptimize and reduce relative error. The parameters used tocreate the comparison curves were output and used in thenext optimization step. Final optimization provided us theability to adjust individual model parameters and monitor theeffects on the curves. An interactive dynamic SPICE-in-the-loop rubber-banding program was used to achieve the results.By using this method, the model parameters were fine-tunedto accurately match the measured data. This type of “curvestretching” or “rubber-banding” was necessary to achieve thehigh level of accuracy needed to create the ASET transistormodels.

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Fig. 2a. Forward Gummel (IC, IB, vs. VBE) of a representativevertical NPN transistor included in the OP27. The gain (beta) curvewas extracted from this data by plotting IC / IB versus VBE .

Fig. 2b. Forward family of curves IC vs. VCE of a representativevertical NPN transistor included in the OP27. The base current washeld constant for each sweep, starting at 1µA up to 5µA.

Fig. 2c. Reverse Gummel (IE, -IB, vs. VBC) of a representativevertical NPN transistor included in the OP27. The reverse gain (beta)curve was extracted from this data by plotting IE / IB versus VBC .

Fig. 2d. Reverse family of curves IE vs. VEC of a representativevertical NPN transistor included in the OP27. The base current washeld constant for each sweep, starting at 1µA to 5µA.

Fig. 2e. Junction capacitance curve taken from the base-collector ofa representative vertical NPN transistor included in the OP27. Thistype of sweep was performed on all active junctions of the transistorbeing measured.

IV. MODELING OF THE OP27 OPERATIONAL AMPLIFIER

A. Schematic/Net-list Extraction

Once transistor level models were extracted for each of therepresentative transistors, they were ready to be implementedinto a SPICE schematic / net-list of the OP27. As with mostmanufacturer-supplied datasheets, the provided schematicwas very simplified. While simplified representations areacceptable for understanding the main portions of the circuitor for macro-modeling purposes, they do not represent theentire circuit. For accurate single event modeling the entirecircuit must be accounted for, including special function areasand biasing transistors [8]. To attain the detailed schematic,multiple high-resolution photomicrographs were taken in agrid pattern and placed together to form a full image of thecircuit layout. The layout was then analyzed and transferredto schematic form. The different sizes of the transistors wereaccounted for by adding scaling factors, which are ratios ofthe emitter area or perimeter compared to the modeledtransistor. Current drive and internal biasing are controlled bythe size of the transistors and must be correct for properoutput response of the circuit. Once complete, the detailedSPICE net-list was prepared for the simulator and tested forfunctionality.

B. Electrical Calibration

The functionality of the circuit net-list was first tested forelectrical response. Common electrical characteristics such asthe large and small signal electrical response, which can beseen in the datasheet, were chosen for our study [9]. Thelarge signal response allowed the model to be tested againstlarge nonlinear voltage variations, while the small signalrepresented lower voltage variations and a high frequency

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response. Both of these characteristics are important for SETsimulations, as shown in [4].

The large signal response was tested in the sameconfiguration as defined by the datasheet: voltage followerwith unity gain, positive and negative supply voltage of + 15volts, and a feedback resistor of 1Kohms. A large voltagesquare pulse, with amplitude of 10 volts and duration of 13µs,was applied to the positive input terminal. After calibrationthe simulated curve closely reproduced the actual curvemeasured in the laboratory. The speed and stability with largevoltage transitions was proven with this validation. Thecomparison of the large signal response, measured versussimulated, can be seen in Fig. 3.

Most operational amplifiers do not require a feedbackresistor when operated at unity gain. The OP27 hasprotection diodes at the input, which effectively short theoutput to the input when the input is driven by a large pulsegreater than 1 volt [9]. To test the full functionality of themodel this protection feature was measured and simulated.The same configuration was used as described before, withthe exception of reducing the feedback resistor from 1 Kohmsto less than 100 ohms. As seen in Fig. 4, the simulated modelreproduces the same protection trend as was measured.During the protection mode the output shorts to the input,which causes the signals to become identical with theexception of a small variation at the top of the rising edge andbottom of the falling edge. This showed that the model wasable to reproduce not only typical characteristics, but alsoapplication specific characteristics.

The small signal response was also tested in theconfiguration defined by the datasheet: voltage follower withunity gain, positive and negative supply voltage of + 15 volts,load capacitance of 15pF, and no feedback resistor. Input forthe configuration was a small signal square wave withamplitude of 100mV, and duration of 1.8µs. Simulation of thesmall signal response was able to reproduce the measuredcurve with little variation, and can be seen in Fig. 5. Thefrequency response of the model was validated with this testalong with the ability overcome low voltage transitions.Transients produced from ion strikes have a high frequencyresponse and it is important that the model be able toreproduce that trend.

Fig. 3. Large signal response of the OP27, comparison betweenmeasured and simulated data.

Fig. 4. Large signal response of the OP27, comparison betweenmeasured and simulated data. Feedback resistor was reduced to < 100ohms to test the ability of the model to reproduce the protectionfunction of the circuit.

Fig. 5. Small signal response of the OP27, comparison betweenmeasured and simulated data.

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V. MODEL VALIDATION TO LASER SET DATA

The extracted transistor net-list and model parameters ofthe OP27 were able to reproduce the typical large and smallsignal characteristics that can be found in the manufacturersdatasheet. To establish if the model’s internal transientcharacteristics produced by SET current pulses were accuratewe chose to perform laser tests. It has been shown that laserscan be used to create electron-hole pairs in semiconductormaterials paralleling the effects of heavy ions [10]. The laserexperiments used for this study were performed at the NavalResearch Laboratory using a 590nm wavelength,approximately 2µm penetration depth, and pulse duration of1ps. Two different laser energies were used during the testing,which equated to approximately 16pC and 42pC. The inducedcharge was equated by monitoring the laser pulse energy witha calibrated large-area photodiode and converting it intodeposited charge by correcting for reflection losses andassuming that each photon gives rise to a single electron-holepair.

The configuration chosen for the experiments was aninverting amplifier with a gain of 20. Fig. 6 shows arepresentation of the test configuration for the laser testsincluding resistor values and input voltage. All the devicesincluded in the OP27 were exposed to the laser to determinetheir SET sensitivity. Approximately half of the devicesshowed SET vulnerability, while the other half had very smallor no transients created from the laser. The devices that weresensitive produced a variety of waveforms, with varyingamplitudes and time widths. The transistors that weresensitive were located throughout the circuit and includedeach of the different stages of the op amp. For our study, allof the transient locations were simulated by applying acurrent source between the junctions, and most were able tobe reproduced with little calibration. The majority of thetransistors produced the correct waveform shape and onlyrequired either calibration on the amplitude or time width. Tocorrect the width of the pulse, the junction capacitances wereadjusted, slightly increased to widen the pulse width, orreduced to shorten. While the junction capacitances hadmarginal effect on the transient amplitude, the main parameterto calibrate the amplitude was adjusting the scaling factor ofthe transistor in question.

Fig. 6. OP27 inverting circuit configuration used in laser tests. Thecombination of the resistors creates a closed loop voltage gain of –20V/V.

Fig. 7 shows a comparison between simulated andexperimental laser output transients for several transistorslocated throughout the OP27. The first waveform (a) wasproduced from a lateral PNP located in the input stage. Thistransistor is part of a group of biasing devices that providesinput stage current drive. This transient has a large negativeamplitude and a long response time. Due to the amplitude andtime width of the transient, it was classified as one of the mostsignificant. The group of devices, which comprise thisbiasing circuitry, produce similar transients, so it wasimportant to accurately model the response. The next set ofwaveforms, (b) and (c), represent output transients withopposite amplitudes. Both were produced by vertical NPNtransistors, one in the gain stage and the other in the outputstage. The transistor in the gain stage serves as a member ofa pair of biasing transistors. The transient noticed haspositive amplitude with a fast response time. The transientseen in (c) had a similar response, but with much higheramplitude and instantaneous response time. Good agreementis shown between the simulated and experimental curves, withthe exception of a smoother transition in the recovery on thefalling edge of the transient in figure (c). The last transientshown (d) is produced from a NPN in the signal path of thecircuit. It has a different shape than the other transients seenin the circuit. A large amplitude negative transient isproduced, which has overshoot on the rising edge. Thistransient was also important to reproduce due to the repetitiveoccurrence throughout the testing procedure.

High frequency (AC) calibration of capacitances and drivecurrent proved crucial to accurate ASET modeling. Whilethese minor parameter changes showed significant results tothe transient response of the individual transistors, it had littlenoticeable effect on the basic electrical response. Laserexperiments proved to be an essential tool to calibrate theaccurate ASET transistor level model. This was achieved bythe laser’s ability to focus on individual transistor junctions,while measuring the output transients created. With the goodagreement of the simulated transient waveforms, it is assumedthat the model can be extended to other applications,including different configurations.

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(a)

(b)

(c)

(d)

Fig. 7. Comparison of output voltage transients created by lasertesting and simulations on the same transistor of the OP27. The laserwas simulated by a current source applied at the Collector-Base junctionof each transistor, with a total integrated charge of approximately 42

pC. The amplitudes and time widths are representative of the measureddata, which validates the internal transient accuracy of the model.

VI. MODEL VALIDATION TO BROAD-BEAM SET DATA

A final validation method for the extracted model was tosimulate mission specific type testing, such as heavy ionbroad beam experiments. Broad beam experiments have nospatial resolution and a large range in charge deposition,which make them more representative of space environments.In this work the experiments were used ensure propercalibration of the model by examining the significant anddominant transient trends that were produced.

The broad beam testing on the OP27 was performed atTAMU cyclotron facility under two different circuitconfigurations with multiple input biases. The firstconfiguration, seen in Fig. 8, was similar to the setup used inthe laser experiments, inverting amplifier with a gain of 10. Byusing a similar circuit configuration, we were able to confirmthe laser calibration and verify the most significant transientscreated by heavy ions. The second configuration chosen wasdifferent than that used in the laser calibration. The circuitwas a non-inverting amplifier with a closed loop gain of 10 asshown in Fig. 9. The input biases for these configurationsranged from –1 volt to 1 volt, which allowed a range ofoperating conditions, and transient behavior.

Fig. 8. OP27 inverting circuit configuration used in broad beam tests.The combination of the resistors creates a closed loop voltage gain of -10 V/V. The input voltage was stepped from –1 volt to 1 volt fordifferent test runs to provide a range of operating conditions.

Fig. 9. OP27 non-inverting circuit configuration used in broad beamtests. The combination of the resistors creates a closed loop voltagegain of 10 V/V. The input voltage ranged from –1 volt to 1 volt fordifferent test runs to provide a range of operating conditions.

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As noted earlier the most significant (worst case) transientscaused by the laser had a negative amplitude, and large timewidth. Broad beam experiments were performed to verify thetrend and confirm the ability of the model to reproducetransients created by heavy ions. Unlike laser irradiation,broad beam experiments create ion strikes in random locationsand have the ability to hit multiple junctions. An appropriateway to view SETs produced by heavy ion irradiation in amicrocircuit, is to plot SET amplitude as a function of pulsewidth. This type of plot takes all transients into account, andclearly shows the trends of the entire circuit. Fig. 10 and 11show broad beam results from both circuit configurations. Asseen from the circled areas, both configurations are dominatedby negative going transients with pulse widths between 4 and6 microseconds. This proves that the laser calibration andmodel were correct in identifying the most significanttransient trend, as shown in Fig. 7a.

Fig. 10. Broad beam data taken at the output of the invertingconfiguration of the OP27 with an input bias of 0.4 volts. Each pointrepresents an individual measured transient. The ions used during thisexperiment are 100MeV, 150MeV, 200MeV, 250MeV, and 283MeVNeon. The circled region represents the major trend in the transientbehavior for the inverting case.

Fig. 11. Broad beam data taken at the output of the non-invertingconfiguration of the OP27. Each point represents an individualmeasured transient and is displayed by amplitude versus pulse width.The ion used during this experiment was kept constant at 200MeVNeon, while the input bias was changed to monitor bias effects. Thecircled region represents the major trend in the transient behavior forthe non-inverting case.

Figure 10 is a representation of the broad beam results onthe inverting circuit configuration. Ions of increasing energywere used to achieve a full range of ion track depths andcharge deposition. The ion chosen was Neon, with a startingenergy of 100MeV and final energy of 283MeV. As seen inthe figure the transient trend is common for the increasingenergy, with no unexplainable new trends. The model has thesame behavioral trends when ion strikes on the individualtransistor junctions are simulated. The amplitude and timewidth slowly increase as the simulated deposited charge isincreased on the group of transistors that cause the behavior.Another result of the broad beam tests can be seen in Fig. 11.Output transients of the non-inverting configuration arerepresented as a function of amplitude versus time width. Inthis figure only one ion energy was used, 200 MeV Neon,while the input bias was changed. As noted previously thesame negative transient trend appears, which verifies that thetrend is not configuration specific. Also shown, is theindependence of input bias on the transient behavior. Theinput bias was stepped in a manner to include a range ofoperating conditions. In the different conditions thetransients created are approximately the same and overlap onthe presented figure. This was also seen with the model andvalidates the ability to correctly represent multipleconfigurations and operating conditions.

VII. SUMMARY AND CONCLUSIONS

We have presented a method to extract transistor levelmodels for use in computer simulation. The FIB is adiagnostic tool that allows characteristic curves to beextracted from devices that are included in packaged parts.The curves are then transferred to SPICE parameters andoptimized using various computer routines. Electricalcalibration was performed by comparing large and small signalcharacteristics, while internal SET sensitivity was explored bylaser experiments. ASET simulations using the extractedmodels reproduced transient trends for the sensitivetransistors. Broad beam experiments were used to achieverepresentative space environments and compare thesignificant transient trends. This process gives researchersinterested in SETs a method to produce accurate transientresults at a low cost.

VIII. ACKNOWLEDGMENT

The authors would like to thank Lew Cohn of DTRA forsupporting this effort.

IX. REFERENCES

[1] A.L. Sternberg, L.W. Massengill, R.D. Schrimpf, Y. Boulghassoul,H.J. Barnaby, S. Buchner, R.L. Pease, and J.W. Howard, “Effectof Amplifier Parameters on Single-Event Transients in anInverting Operational Amplifier,” IEEE Trans. Nucl. Sci., vol.49, no. 3, pp. 1496-1501, June. 2002.

[2] A.L. Sternberg, L.W. Massengill, R.D. Schrimpf, and P. Calvel,“Application Determinance of Sinlge-Event Transient

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Characteristics in the LM111 Comparator,” IEEE Trans. Nucl.Sci., vol. 48, no. 6, pp. 1855-1858, Dec. 2001.

[3] R.L. Pease, A.L. Sternberg, L.W. Massengill, R.D. Schrimpf, S.Buchner, M.W. Savage, J.L. Titus, and T.L. Turflinger, “CriticalCharge for Single-Event Transients (SETs) in Bipolar LinearCircuits,” IEEE Trans. Nucl. Sci., vol. 48, no. 6, pp. 1966-1972,Dec. 2001.

[4] Y. Boulghassoul, L.W. Massengill, A.L. Sternberg, R.L. Pease, S.Buchner, J.W. Howard, D. McMorrow, M.W. Savage, and C.Poivey, “Circuit Modeling of the LM124 Operational Amplifierfor Single-Event-Transient Analysis,” IEEE Trans. Nucl. Sci., vol.49, no. 6, pp. 3090-3096, Dec. 2002.

[5] G.R. Matusiewicz, S.J. Kirch, and V.J. Seeley, “The role of focusedion beams in physical failure analysis [ICs],” Proc. 29th AnnualInternational Reliability Physics Symposium, IRPS’91, pp. 167-170, April 1991.

[6] J. Benbrik, P. Perdu, B. Benteo, R. Desplats, N. Labat, A.Touboul, and Y. Danto, “Induced damages on CMOS and bipolarintegrated structures under focused ion beam irradiation,”Microelectronics Reliability, vol. 38, pp. 901-905, June 1998.

[7] DAKOTA User’s Manual[8] Y. Boulghassoul, J.D. Rowe, and L.W. Massengill, “Applicability

of Circuit Macromodeling to Analog Single-Event TransientAnalysis,” IEEE Trans. Nucl. Sci., vol. 50, no. 6, Dec. 2003.

[9] Analog Devices, Inc. OP27 Low-Noise Precision OperationalAmplifier. [Online]. Available: www.analog.com

[10] S. Buchner, D. McMorrow, J. Melinger, and A.B. Campbell,“Laboratory tests for single-event effects,” IEEE Trans. Nucl.Sci., vol. 43, pp. 678-686, Apr. 1996.