Steven S. McClure

Mechanisms of Enhanced Radiation-Induced Degradation Due to Excess Molecular Hydrogen in Bipolar Oxides

Bipolar junction test structures packaged in hermetically sealed packages with excess molecular hydrogen (H2) showed enhanced degradation after radiation exposure. Using chemical kinetics, we propose a model that quantitatively establishes the relationship between excess H2 and radiation-induced interface trap formation. Using environments with different molecular hydrogen concentrations, radiation experiments were performed and the experimental data showed excellent agreement with the proposed model. The results, both experimentally and theoretically, showed increased radiation induced degradation with H2 concentration, and device degradation saturate at both high and low ends of H2 concentrations.

Total dose degradation of MEMS optical mirrors

This paper discusses the effect of ionizing radiation on two types of deformable MEMS mirrors. Little effect was observed in the technology that was based on electrostatic deflection, consistent with the structural design that does not contain insulators between the two sections. Significant changes in the operating characteristics were observed for the second type of mirror, which uses piezoelectric material for actuation. The mirrors required higher total dose levels before they were affected compared with MEMS accelerometers, which can be explained by the larger interelement spacing used in the mirror arrays.

Irradiation With Molecular Hydrogen as an Accelerated Total Dose Hardness Assurance Test Method for Bipolar Linear Circuits

High dose rate irradiation with hydrogen stress is proposed as an accelerated total dose test method for bipolar linear circuits. The method is validated across process and circuit technologies with five parts that are commonly used in space: a comparator (LM193 from National Semiconductor), a voltage regulator (HSYE-117 RH from Intersil), a voltage reference (LT1019 from Linear Technology), a JFET input op amp (OP42 from Analog Devices) and a temperature transducer (AD590 from Analog Devices). The testing technique could rapidly establish an upper bound to the low dose rate response of parts in space and help with the part selection process in the design phase of a mission. Radiation hardness assurance implications are discussed.

Catastrophic SEE in high-voltage power MOSFETs

Heavy ion irradiation of high-voltage power MOSFETs with long-range ions (>123/spl mu/m in silicon) was performed using 14, 19, 22, 24, 28, and 39 MeV-cm/sup 2//mg ions at normal incidence. Prior to catastrophic failure some DUTs exhibited unusual electrical characteristic: all devices demonstrated high current transients (or current spikes) at voltages significantly lower than the voltage at which the devices failed.

Recent radiation test results at JPL

This paper documents recent TID (including ELDRS) and proton damage test results obtained by JPL. Unusual test results, such as abnormally low or high failure levels or unusual failure or response mechanisms, are emphasized.

ELDRS Characterization for a Very High Dose Mission

Evaluation of bipolar linear parts which may have Enhanced Low Dose Rate Sensitivity (ELDRS) is problematic for missions that have very high dose radiation requirements. The accepted standards for evaluating parts that display ELDRS require testing at a very low dose rate which could be prohibitively long for very high dose missions. In this work, a methodology for ELDRS characterization of bipolar parts for mission doses up to 1 Mrad(Si) is evaluated. The procedure employs an initial dose rate of 0.01 rad(Si)/s to a total dose of 50 krad(Si) and then changes to 0.04 rad(Si)/s to a total dose of 1 Mrad(Si). This procedure appears to work well. No change in rate of degradation with dose has been observed when the dose rate is changed from 0.01 to 0.04 rad(Si)/s. This is taken as an indication that the degradation due to the higher dose rate is equivalent to that at the lower dose rate at the higher dose levels, at least for the parts studied to date. In several cases, significant parameter degradation or functional failure not observed at HDR was observed at LDR at fairly high total doses (50 to 250 krad(Si)). This behavior calls into question the use of dose rate trend data and enhancement factors to predict LDR performance.

Comparison of TID Effects in Space-Like Variable Dose Rates and Constant Dose Rates

The degradation of the LM193 dual voltage comparator has been studied at different TID dose rate profiles, including several different constant dose rates and a variable dose rate that simulates the behavior of a solar flare. A comparison of results following constant dose rate vs. variable dose rates is made to explore how well the constant dose rates used for typical part testing predict the performance during a simulated space-like mission. Testing at a constant dose rate equal to the lowest dose rate seen during the simulated flare provides an extremely conservative estimate of the overall amount of degradation. A constant dose rate equal to the average dose rate is also more conservative than the variable rate. It appears that, for this part, weighting the dose rates by the amount of total dose received at each rate (rather than the amount of time at each dose rate) results in an average rate that produces an amount of degradation that is a reasonable approximation to that received by the variable rate.

Compendium of Test Results of Recent Single Event Effect Tests Conducted by the Jet Propulsion Laboratory

This paper reports heavy ion and proton-induced single event effect (SEE) results from recent tests for a variety of microelectronic devices. The compendium covers devices tested over the last two years by the Jet Propulsion Laboratory.

TID Test Results for 4th Generation iPad

TID testing results of 4th generation iPad tablet computers are reported. Of iPad subsystems, results indicate that the charging circuitry and display drivers fail at lowest TID levels. Details of construction are investigated for additional testing of components.

Degradation of RH1056 parameters at low total dose

The behavior of the RH1056 JFET input operational amplifier from linear technologies following Co-60 irradiation has been studied at both high and low dose rates. A significant amount of unexpected degradation of the input offset voltage for this radiation hardened part is observed at low doses. The amount of degradation peaks between about 2 and 6 krad(Si) depending on irradiation conditions. At higher doses, above about 20 krad(Si), the input offset voltage recovers to near pre-irradiation values. This degradation at low doses is not anticipated by the manufacturers data sheet and could present unexpected surprises for missions operating in the total dose range of 2 - 10 krad(Si). This performance also suggests some potential issues with the typical hardness assurance methodology of step-level testing if the steps are too large.