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

2. 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

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

4. 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.

5. Electron Belts

6. Proton Belts

7. 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)

8. 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

9. 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

10. 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

11. Space Station. 1 year dose-depth curve.

12. Space Station . Non-Ionizing Energy Loss spectrum.

13. Space Station. Orbit averaged LET spectra

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

15. 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

16. 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.

17. 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’

18. Single Event Current Pulse

19. SEU Mechanism in CMOS bistable

20. 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’)

21. 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.

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

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

24. 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.

25. 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

26. 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.

27. 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.

28. Dose-rates for testing.
- High Dose Rate:
SCC Window rads/sec.
MIL883E rads/sec.
Low Dose Rate:
SCC Window rads/sec.
MIL883E rads/sec.
Elevated Temp rads/sec.

29. 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.

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

31. 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.

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

33. 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 (?)

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

35. 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

36. 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.

37. 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.

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

39. 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.

40. 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

42. 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.

43. 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

44. 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

45. 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.

46. 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.

47. 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

48. 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.

49. 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

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