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ABSTRACT: Dose-rate effects are studied in shallow trench isolation regions. Increased damage is observed at low dose rate, with a different dose dependence compared to tests done at high dose rate. A three-dimensional modeling program was used to show that charge trapping occurs much deeper in the trench region when sufficient charge is present to reduce the field in the trench.
IEEE Transactions on Nuclear Science 01/2011; · 1.45 Impact Factor
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ABSTRACT: Failure modes are investigated for linear integrated circuits, including op-amps that are embedded within more complex circuit functions. The specific techniques used in internal circuit design have a large impact on the radiation sensitivity of various device parameters, which makes it difficult to generalize conclusions about failure mechanisms. Loading and bias conditions can be critically important for some devices, and have a large impact on hardness assurance.
IEEE Transactions on Nuclear Science 09/2010; · 1.45 Impact Factor
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ABSTRACT: Operating principles and hardness assurance methods are discussed for various types of optocouplers. Radiation damage in light-emitting diodes is addressed, along with the impact of phototransistors and internal amplifiers on overall performance. Hardness assurance for optocouplers is contrasted with the approach used for conventional microelectronics. Methods of detecting abnormal devices are discussed, along with the implementation of special screening measurements.
IEEE Transactions on Nuclear Science 01/2010; · 1.45 Impact Factor
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ABSTRACT: A model for inversion in trench isolation is developed using an analytical model to calculate the surface charge density along the trench sidewall. The model shows that the inversion path takes place well below the trench corner for devices with 180 nm feature size. The increased hardness of highly scaled devices is caused by a combination of higher doping levels and a decrease in the lateral charge collection path within the trench.
IEEE Transactions on Nuclear Science 09/2009; · 1.45 Impact Factor
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ABSTRACT: This paper discusses total dose damage in operational amplifiers with compensated input stages. The impact of this design approach on unit-to-unit variability of radiation damage is examined, along with hardness assurance methods that can be used to bound the radiation behavior. Data is included for an unusually large sample (100 devices) of one device type. Half of those devices were subjected to burn-in before irradiation to investigate the effect of burn-in on radiation response.
IEEE Transactions on Nuclear Science 09/2008; · 1.45 Impact Factor
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ABSTRACT: Radiation damage is examined for several different LED technologies used in optocouplers, including those with wavelengths near 700 nm that are used in radiation-tolerant devices, and have not been widely studied. Forward diode characteristics and reverse recovery time measurements are examined as potential parameters for hardness assurance.
IEEE Transactions on Nuclear Science 01/2008; · 1.45 Impact Factor
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ABSTRACT: This paper discusses total dose damage in operational amplifiers with compensated input stages. The impact of this design approach on unit-to-unit variability of radiation damage is examined, along with hardness assurance methods that can be used to bound the radiation behavior. Data is included for an unusually large sample (100 devices) of one device type. Half of those devices were subjected to burn-in before irradiation to investigate the effect of burn-in on radiation response.
Radiation and Its Effects on Components and Systems, 2007. RADECS 2007. 9th European Conference on; 10/2007
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ABSTRACT: Radiation damage is investigated in optocouplers with power MOSFET output stages. They differ from conventional optocouplers, incorporating an intermediate photovoltaic chip to allow the MOSFET gate voltage to be controlled by the light-emitting diode. These optocouplers are sensitive to ionization as well as displacement damage, and can fail catastrophically from degradation in either the power MOSFET or the LED. Radiation testing must take both mechanisms into account.
IEEE Transactions on Nuclear Science 09/2007; · 1.45 Impact Factor
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ABSTRACT: Single-event transients are investigated for two voltage regulator circuits that are widely used in space. A circuit-level model is developed that can be used to determine how transients are affected by different circuit application conditions. Internal protection circuits-which are affected by load as well as internal thermal effects-can also be triggered from heavy ions, causing dropouts or shutdown ranging from milliseconds to seconds. Although conventional output transients can be reduced by adding load capacitance, that approach is ineffective for dropouts from protection circuitry
IEEE Transactions on Nuclear Science 01/2007; · 1.45 Impact Factor
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ABSTRACT: Hardness assurance methods are examined for several types of optocouplers. A new diagnostic method using reverse-recovery time has a strong correlation with damage in the internal light emitting diode (LED). It depends only on electrical measurements, and can be used as a first-order parameter to determine LED properties when the LED technology of the optocoupler is unknown, as well as for evaluating unit and lot variability. For devices with internal LEDs that are highly sensitive to displacement damage, the dependence of phototransistor gain on operating conditions can impact post-radiation performance. For devices with radiation-tolerant LEDs, phototransistor characteristics and gain degradation are both important in determining the net effect of displacement damage.
IEEE Transactions on Nuclear Science 01/2006; · 1.45 Impact Factor
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ABSTRACT: This paper discusses mechanisms and circuit-related factors that affect the degradation of linear integrated circuits from radiation in space. For some circuits there is sufficient degradation to affect performance at total dose levels below 4 krad(Si) because the circuit design techniques require higher gain for the pnp transistors that are the most sensitive to radiation. Qualification methods are recommended that include displacement damage as well as ionization damage.
Radiation and Its Effects on Components and Systems, 2005. RADECS 2005. 8th European Conference on; 10/2005
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ABSTRACT: A low dropout voltage regulator that uses a lateral pnp transistor as a pass transistor in the output stage is evaluated for total dose degradation. Degradation occurs from two different mechanisms, one involving gradual degradation due to changes in internal reference voltage resulting in small changes in output voltage saturation characteristics; and the other causing the output voltage to fall to nearly zero because of gain degradation in the lateral pnp output transistor. Additionally, wide variability was observed between two different lots of devices, produced approximately 18 months apart. This illustrates the importance of lot-sample testing when these highly sensitive devices are considered for use in space.
Radiation Effects Data Workshop, 2005. IEEE; 08/2005
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ABSTRACT: This paper describes total ionizing dose (TID) test results performed at JPL. Bipolar and BiCMOS device samples were tested exhibiting significant degradation and failures at different irradiation levels. Linear technology which is susceptible to low-dose dependency (ELDRS) exhibited greater damage for devices tested under zero bias condition.
Radiation Effects Data Workshop, 2005. IEEE; 08/2005
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ABSTRACT: Proton damage is investigated for LEDs with wavelengths of 1050 and 1550 nm. The results are compared to results for an advanced AlGaAs double heterojunction LED. Unlike the AlGaAs LED, light output degradation for the long wavelength LEDs became nonlinear with current after irradiation; more degradation was observed at lower forward currents. Minimal annealing was observed in the long wavelength LEDs during forward current injection. Mechanisms are proposed that are related to the material properties.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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ABSTRACT: Degradation mechanisms are investigated for laser diodes fabricated with different materials and wavelengths between 660 and 1550 nm. A new approach is developed that evaluates laser degradation below the laser threshold to determine the radiation-induced recombination density. This allows mechanisms at high injection, such as Auger recombination, to be separated from low-injection damage. New results show that AlGaInP lasers in the visible region are nearly an order of magnitude more resistant to radiation damage than devices fabricated with AlGaAs or InGaAsP at longer wavelengths.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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ABSTRACT: InGaAs and Ge avalanche photodiodes (APDs) are examined for the effects of 63-MeV protons on dark current. Dark current increases were large and similar to prior results for silicon APDs, despite the smaller size of InGaAs and Ge devices. Bulk dark current increases from displacement damage in the depletion regions appeared to be the dominant contributor to overall dark current degradation. Differences in displacement damage factors are discussed as they relate to structural and material differences between devices.
IEEE Transactions on Nuclear Science 01/2005; · 1.45 Impact Factor
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ABSTRACT: This paper reports recent total ionizing dose (TID) test results obtained at JPL. Several device samples were analyzed exhibiting significant failure levels and enhanced low dose rate sensitivity (ELDRS) effects under biased and unbiased conditions.
Radiation Effects Data Workshop, 2004 IEEE; 08/2004
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ABSTRACT: A recent failure of Galileo's magnetic recorder was attributed to LED degradation. Annealing the culprit OP133 proved successful: irreplaceable data, taken during the encounter with Jupiter's previously unvisited moon Amalthea, was recovered. Annealing test data for both proton and electron displacement damage combined with a simple device temperature model explains some details of the failure and the partial recovery of recorder motor function.
IEEE Transactions on Nuclear Science 01/2004; · 1.45 Impact Factor
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A.H. Johnston
IEEE Transactions on Nuclear Science 01/2004; · 1.45 Impact Factor
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ABSTRACT: Different silicon avalanche photodiode structures are compared for the effects of 51-MeV protons on dark current, photocurrent, and noise. Large differences in depletion region volumes contributed to differences in sensitivity to bulk dark current increases. At high fluences, ionization damage appeared to be the dominant mechanism for dark current increases in some devices. Increases in 1/f-type noise and supplemental gamma ray testing indicate that these high dark current increases are due to surface damage effects. A discussion of structural parameters that may heighten radiation sensitivity is presented, including doping levels and p-n junction termination techniques.
IEEE Transactions on Nuclear Science 01/2004; · 1.45 Impact Factor
