Space Radiation Effects in Electronic Components. Len Adams Professor Associate, Brunel Univ. Consultant to Spur Electron. For: PA and Safety Office. May 2003

Space Radiation Effects in Electronic Components Structure of Presentation Space radiation environment Radiation effects in electronic components. Radiation testing Use of commercial components Guide to comrad-uk resource Open discussion

Space Radiation Environment Overview Complex and Dynamic Trapped Radiation – ‘Belts’ of energetic electrons and protons Cosmic Rays (Energetic Ions) Solar Event protons

Space Radiation Environment Trapped Radiation Electrons and Protons are trapped in the Earths magnetic field, forming the ‘Van Allen’ belts. Electrons up to 7 MeV Protons up to a few hundred MeV.

Electron Belts

Proton Belts

Space Radiation Environment Transiting Radiation Very high energy Galactic Cosmic Rays originating from outside the solar system Solar Events. (X-rays, protons and heavy ions)

Space Radiation Environment Galactic Cosmic Rays 85% Protons, 14% Alpha particles, 1% Heavy Nuclei. Energies up to GeV Expressed in terms of Linear Energy Transfer (LET) for radiation effects purposes

Space Radiation Environment Solar Flares Occur mostly near first and last year of solar maximum Solar Events, composed mainly of protons with minor constituent of alpha particles, heavy ions and electrons

Space Radiation Environment South Atlantic Anomaly Distortion of the earth’s magnetic field allows the proton belts to extend to very low altitudes in the region of South America Low Earth Orbiting satellites will be exposed to high energy protons in this region

Space Station. 1 year dose-depth curve.

Space Station . Non-Ionizing Energy Loss spectrum.

Space Station. Orbit averaged LET spectra

Space Station. Proton flux as a function of orbital time.

Radiation Effects in Components (1) IONIZATION Mechanism : Charge generation, trapping and build-up in insulating layers. Due to: Electrons, Protons. Main Effects: Parameter drift. Increased leakage currents. Loss of noise immunity. Eventual functional failure

Radiation Effects in Components (2) DISPLACEMENT DAMAGE Mechanism: Disruption of crystal lattice Due to: Protons Main Effects: Reduced gain, increased ‘ON’ resistance, reduced LED output, reduced charge transfer efficiency in CCDs.

Radiation Effects in Components (3) SINGLE EVENT Mechanism: Dense path of localised ionization from a single particle ‘hit’ Due to: Cosmic rays, high energy protons. Main Effects: Transient current pulses, variety of transient and permanent ‘Single Event Effects’

Single Event Current Pulse

SEU Mechanism in CMOS bistable

Radiation Effects in Components (4) Single Event Effects in detail Latch-up. Permanent, potentially destructive Bit flips (‘Single Event Upset’) in bistables High Anomalous Current (HAC), ‘snap-back’ Heavy Ion Induced Burn-out in power MOS Single Event Gate Rupture (SEGR) Single Event Transient, noise pulses, false outputs ‘Soft Latch’ (device or system ‘lock up’)

Typical Single Event Transient Requirements. Output voltage swing of rail voltage to ground and ground to rail voltage. Duration: 15 microseconds for Op-Amps. 10 microseconds for comparators, voltage regulators and voltage references. 100 nanoseconds for opto-couplers.

Radiation Testing Specifications and Standards Total Ionizing Dose: SCC-22900 (ESA-SCC) Mil Std 883E Method 1019.6 (DESC) ASTM F1892 (includes ELDRS) Single Event: SCC-29500 (ESA-SCC) EIA/JEDEC Standard EIA/JESD57 ASTM F1192

Radiation Testing Important Considerations Choice of radiation source. Specifications and Standards Worst case or application bias Test software Number of samples Traceability Databasing

Radiation Testing Choice of Source Total Ionizing Dose: Co-60 gamma or 1-3 MeV electrons (Linac or VdG) Displacement Damage: Protons (10-20 MeV), Neutrons (1 MeV), Electrons (3-5 MeV) Single Event: Heavy Ion Accelerator (ESA-Louvain HIF), Proton Accelerator (ESA-PSI PIF) Cf-252 ‘CASE’ laboratory system.

Typical Radiation Verification (RVT) requirements. TECHNOLOGY REQUIREMENT DOSE RATE Bipolar Transistor Data > 10 yrs High or Low MOS Transistor All diffusion lots Linear ICs Low MOS Digital ICs Data > 1 yr Bipolar Digital ICs ASICs, FPGA. Data > 2 yrs MOS RAM, ROM Bipolar RAM, ROM Data > 6 yrs Optoelectronics

Technologies generally considered to be radiation tolerant (~ 300 krad) Diodes (other than zener). TTL logic (e.g. 54xx series). ECL (Emitter Coupled Logic). GaAs (Gallium Arsenide) technologies. Microwave devices. Crystals. Most passives.

Radiation Testing Sample Size/Traceability Total Ionizing Dose. Minimum 5 samples. 4 test, 1 reference. Single Event. 3 samples recommended. Traceability: Use single Lot-Date-Code for test and flight hardware.

Dose-rates for testing. - High Dose Rate: SCC 22900 Window 1. 1-10 rads/sec. MIL883E 1019.6. 50-300 rads/sec. Low Dose Rate: SCC 22900 Window 2. 0.01-0.1 rads/sec. MIL883E 1019.6. 0.01 rads/sec. Elevated Temp. 0.5-5 rads/sec.

Radiation Testing Test Software (Single Event) Test pattern dependence. All 1, All 0, Alternate 1-0, Chequerboard, MOVI. Different sensitivities for different registers. Dead Time. (detect flip/record/rewrite) How to test Processors (‘Golden Chip’ ?) Possibility to run application software ? Beware of software/hardware interaction.

Radiation Testing And finally…… TEST IT LIKE YOU FLY IT FLY IT LIKE YOU TEST IT (Ken LaBel. GSFC)

Use of Commercial Components The use of commercial technology does NOT necessarily result in cost-saving. Cost of Ownership is the important consideration. First choice should always be QML or Space Quality components if available.

Why Use Commercial Technology ? Complexity of functions Performance Availability (limited number of QML/Space suppliers).

What are the drawbacks of commercial technology? Little or no traceability Rapid and unannounced design and process changes. Rapid obsolescence Packaging Issues (Plastic). - Effect of burn-in on radiation response - Deep dielectric charging in space (?)

COTS Hardness Assurance Define the hazard Evaluate the hazard Define requirements Evaluate device usage Discuss with designers Iterate process as necessary

Risk Assessment & Mitigation Components list review by a radiation expert Good Radiation Design Margin (2-5) Fully characterise key components Limit the use of new technologies Eliminate or shield marginal technologies Maintain awareness of developments in radiation effects Do not cut back on testing Look for system solutions

Countermeasures/Mitigation Total Ionizing Dose. Additional shielding. Only effective in electron dominated environments. Cold redundancy (‘sparing’). Not effective for all technologies. Generous derating. Robust electronic design. High drive currents, low fan-out or loading. Large gain margins, high noise immunity etc.

Countermeasures/Mitigation. Single Event Effects Note that additional shielding is NOT effective. Ensure systems are not sensitive to transient effects. Use fault tolerant design techniques. Use Error Detection and Correction for critical circuits. Ensure systems can re-boot autonomously.

COMRAD-UK An integrated Web resource of components radiation effects data.

Why Integrated Web Resource ? COMRAD provides more than a database. it includes : Components radiation effects database. A tutorial handbook. Links to radiation effects sites. Links to manufacturers sites. Links to publications in .pdf format. ‘Experts Forum’ for technical discussions.

Available from COMRAD-UK Home Page Terms Links Glossary Index Search Total Dose Heavy Ion Neutron Proton Sponsors Manufacturers Seminars Handbook Publications & News Experts Forum

Origins of COMRAD-UK Database ESA RADFX (on discs) Database Round Table (RADECS 1993) Discussions with Space Agencies, Scientific Institutes and Industry Discussions with CERN LHC Project and Detector groups.

Aims of COMRAD-UK Database To be ‘informative’ not ‘regulatory’. To contain recent data and be continuously updated. To provide data summary and detailed tabulated data (if available). To provide contact details for the test authority. To be expandable for High-Energy Physics and Avionics

COMRAD-UK Database status. 700 Total Dose records 280 Single Event Records Being updated on a monthly basis Primary data resources: IEEE NSREC Data Workshop and Proceedings RADECS Data Workshop and Proceedings ESA Contract Reports. IEEE Publications. CERN reports and publications

Origins of COMRAD-UK Handbook ESA Radiation Design Handbook. PSS-609 Handbook of Radiation Effects. OUP 1993. The use of commercial components in aerospace technology. BNSC Contract Report 1999. Participation in CERN RD-49 collaboration. ‘Hardened microelectronics and commercial components’. Various international seminars and workshops over past 5 years.

Aims of COMRAD-UK Handbook A brief (100 page) tutorial guide to the space application of components. To assist in the assessment of components in the COMRAD database for any particular mission. Provides guidance on Hardness Assurance practices. Discusses the application of commercial components.

Handbook Contents The Space Radiation Environment Radiation Effects Prediction Techniques Radiation Effects in Electronic Components Designing Tolerant Systems Radiation Effects Databases Radiation Testing Hardness Assurance Management Recommended Procurement Practices

COMRAD-UK Experts Forum The Experts Forum allows users to post queries on the Web-site. These will, as far as possible, be answered by Spur Electron but it is also possible for other users to provide an input and start a discussion.

Summary COMRAD-UK is a Web based integrated source of components radiation effects data. COMRAD-UK is co-sponsored by the British National Space Centre and maintained on their behalf by SPUR-Electron. The site is under continuous development - comments and suggestions are welcome. comrad-uk.net radinfo@spurelectron.com

Hardness Assurance in the real world WE HAVEN’T GOT THE MONEY SO WE’VE GOT TO THINK. (Lord Rutherford 1871-1937)