1. Rad (radiation) Hard Devices used in Space, Military Applications, Nuclear Power in-situ Instrumentation
Savanna Krassau
4/21/2017
Abstract: Environments with large amounts of radiation create design challenges for integrated circuits. A single charged particle can knock loose thousands of electrons, resulting in noise, signal spikes, inaccurate data and worse: total system failure.

2. Introduction to Rad Hard Devices
The Need for Rad Hard Devices
Types of Radiation
Types of Radiation Damage
Rad Hard Solutions
Physical Rad-Hardening Techniques
Logical Rad-Hardening Techniques

3. Dead Robots
Fukushima

4. Outer Space

5. Types of Radiation
Cosmic Rays: protons, alpha particles, heavy ions with x-ray and gamma-ray radiation
Solar Particle Events: from the sun, protons and heavy ions with x-ray radiation
Nuclear Reactors: produce gamma and neutron radiation

6. Types of Radiation Damage
Semiconductors are susceptible to radiation
Perspective: Human workers have a 2-5 rads/year limit. Most commercial electronics can survive ration levels in silicon of at least rads
Single Event Effects
Caused by one single energetic particle
Total Ionizing Dose Effects
A measure of how much radiation has accumulated over the lifetime of the device

7. Single Event Effects in Detail
Single Event Upsets
Errors caused by ionizing the medium they pass through leaving electron-hole pairs
Single Event Latchup
More and more current is dragged into the substrate which can cause the entire circuit to breakdown
Single Event Burnout
A heavy ion passed through a transistor and deposited enough charge to turn the transistor on

8. Total Ionizing Dose Effects in Detail
Cumulative Damage
Measured by Industry
Causes slow gradual degradation of device’s performance
However, a total dose of 5000 rads to delivered to a Si based device seconds to minutes will cause long term damage
Energy is absorbed in SiO2 liberates charge carries which diffuse or drift to other locations where they are trapped

9. Physical Rad-Hardening Techniques
Insulating Substrates
Radiation-tolerant SRAM
Wide band-gap Substrate
Shielding the Package against Radioactivity
Shielding the chips by using Depleted Boron

10. Logical Rad-Hardening Techniques
Error Correcting Memory
Uses parity bit and a scrubber circuit continuously sweeps the RAM
Redundant Elements
Duplication of critical components, or three component voting system
Watchdog Timers
Hard reset if watchdog is allowed to timeout

11. Conclusion
Electronics for Space, the Military, and Nuclear Power Applications have to meet requirements which are very different from those or ordinary consumer products because they need to withstand higher levels of radiation

12. References

13. Five Take Away Points
There is a need for Rad Hard devices because of extreme environments with high levels of radiation
Types of radiation: cosmic, solar, and nuclear
Single Event Effects are caused by a single energized particle
Total Ionizing Dose is cumulative radiation
There are techniques both physical and logical to make devices radiation resistant