James Fred Salzman

Effectiveness of SEL Hardening Strategies and the Latchup Domino Effect

Heavy ion, neutron, and laser experimental data are used to evaluate the effectiveness of various single event latchup (SEL) hardening strategies, including silicon-on-insulator (SOI), triple well, and guard rings. Although SOI technology is widely reported to be immune to SEL, conventional pnpn latchup can occur and has been observed in non-dielectrically isolated SOI processes. Triple well technologies are shown to be more robust against SEL than dual well technologies under all conditions used in this study, suggesting that the introduction of a deep N-well is an excellent zero-area-penalty hardening strategy. A single guard ring is shown to be sufficient for SEL immunity in the 180 nm CMOS technology investigated, and is likely sufficient for more modern CMOS technologies. After triggering latchup in a certain pnpn region, latchup was observed to spread to neighboring pnpn regions, which then infected other more distant regions until it had spread over a total distance of 700 micrometers. We discuss the physical mechanism of this latchup domino effect and its implications for device characterization and hardness assurance.

Intrinsic SEU Reduction from Use of Heterojunctions in Gallium Arsenide Bipolar Circuits

Use of GaAs/AlGaAs heterojunctions at the base emitter junction in MBE-type GaAs bipolar circuits reduces the thickness of the SEU sensitive volume associated with each transistor to about 0.2¿m. This results in a sharply reduced charge collection and a correspondingly sharp reduction in SEU sensitivity even for low values of the critical charge. The effect is illustrated with an HI2L gate array developed at Texas Instruments in which shift registers do not exhibit upsets upon exposure to heavy ions with LET values of up to 20 MeVcm2/mg(GaAs) which is equivalent to over 30 MeVcm2/mg(Si). A low-current version of the same shift registers exhibits an upset cross section of only 3 E-13 cm2/bit at an LET of 20 MeVcm2/mg and zero at 11 MeVcm2/mg(GaAs). Neither of the devices could be upset by exposure to 63 MeV protons at a fluence of 1E + 12 p/cm2 in agreement with the predictions of the CUPID codes.

Current Single Event Effects Compendium of Candidate Spacecraft Electronics for NASA

We present the results of single event effects (SEE) testing and analysis investigating the effects of radiation on electronics. This paper is a summary of test results.

Enhanced Low Dose Rate Sensitivity at Ultra-Low Dose Rates

We present results on the effects of ELDRS at dose rates of 10, 5, 1, and 0.5 mrad(Si)/s for a variety of commercial, radiation hardened, and ELDRS-free devices. We observed low dose rate enhancement below 10 mrad(Si)/s in several different part types. The magnitudes of the low dose rate enhancement varied substantially. The most notable case showed dose rate sensitivity in the functional failures for a commercial voltage regulator, with initial failures occurring after 10 krad(Si) for the parts irradiated at 0.5 mrad(Si)/s. Radiation hardened and ELDRS-free devices also showed ELDRS at the ultra-low dose rates. An ELDRS-free high power regulator showed a low dose rate enhancement factor of ×33 after 10 krad(Si) for parts irradiated at 0.5 mrad(Si)/s. The enhanced degradation at the ultra-low dose rates present challenges for hardness assurance.

The Effects of ELDRS at Ultra-Low Dose Rates

We present results on the effects on ELDRS at dose rates of 10, 5, 1, and 0.5 mrad(Si)/s for a variety of radiation hardened and commercial devices. We observed low dose rate enhancement below 10 mrad(Si)/s in several different parts. The magnitudes of the dose rate effects vary. The TL750L, a commercial voltage regulator, showed dose rate dependence in the functional failures, with initial failures occurring after 10 krad(Si) for the parts irradiated at 0.5 mrad(Si)/s. The RH1021 showed an increase in low dose rate enhancement by 2X at 5 mrad(Si)/s relative to 8 mrad(Si)/s and high dose rate, and parametric failure after 100 krad(Si). Additionally the ELDRS-free devices, such as the LM158 and LM117, showed evidence of dose rate sensitivity in parametric degradations. Several other parts also displayed dose rate enhancement, with relatively lower degradations up to ~ 15 to 20 krad(Si). The magnitudes of the dose rate enhancement will likely increase in significance at higher total dose levels.

Radiation Performance of Commercial SiGe HBT BiCMOS High Speed Operational Amplifiers

We present results on heavy-ion and proton irradiations for commercial SiGe BiCMOS differential amplifiers: LTC6400-20 from Linear Technology and THS4304 from Texas Instruments. We found that the devices are susceptible to heavy-ion-induced SETs, with relatively low LET thresholds (LETth). The LTC6400 exhibits a LETth < 7.4 MeV•cm2/mg for frequencies ranging from 10 to 1000 MHz. The THS4304 exhibits a LETth < 4.4 MeV•cm2/mg at 200 MHz; the LETth decreases with increasing frequency. The SET cross-sections increase with increasing operating frequency. The significance of the SETs also increases with frequency. The SETs at 1000 MHz erase several signal cycles. We also found that the LTC6400 is relatively robust against 198 and 54 MeV protons. We did not observe angular sensitivity from the proton irradiations.

The Use of 14-Mev Monoenergetic Neutrons to Improve the Single Event Latch-Up Response of the Texas Instruments VSP1221

The SEL response of the VSP1221 is improved by exposure to 14MeV monoenergetic neutrons while only causing small changes in the parametric response. This approach could be used to advance COTS components in spaceborne applications.

Single Event Effects Testing of the Hardened Texas Instruments MSP430FR5739 Microcontroller on with Embedded Ferroelectric Memory

MSP430FR55739 tests at the Lawrence Berkeley National Laboratory (LBNL) Cyclotron used the Milli-Beam apparatus to restrict exposure to specific blocks. Instruction lockstep techniques were employed to synchronize test unit outputs with an unexposed device. In this paper, we present cross-sections for the device and functional blocks.

Radiation performance of a monolithic synchronous DC-DC point of load regulator for harsh environments

This work reviews the design and performance of a fully monolithic 6A synchronous buck converter for harsh environments. Radiation test results of total ionizing dose and single event effects are reported for the TPS50601-SP. Extended temperature performance is also discussed. The TPS50601-SP is fabricated in Texas Instruments 7th generation BiCMOS process technology developed for power system products.