Radiation hardening

Not to be confused with hard radiation.

Radiation hardening is the act of making electronic components and systems resistant to damage or malfunctions caused by ionizing radiation (particle radiation and high-energy electromagnetic radiation),[1] such as those encountered in outer space and high-altitude flight, around nuclear reactors and particle accelerators, or during nuclear accidents or nuclear warfare.

Most semiconductor electronic components are susceptible to radiation damage; radiation-hardened components are based on their non-hardened equivalents, with some design and manufacturing variations that reduce the susceptibility to radiation damage. Due to the extensive development and testing required to produce a radiation-tolerant design of a microelectronic chip, radiation-hardened chips tend to lag behind the most recent developments.

Radiation-hardened products are typically tested to one or more resultant effects tests, including total ionizing dose (TID), enhanced low dose rate effects (ELDRS), neutron and proton displacement damage, and single event effects (SEE, SET, SEL and SEB).

Problems caused by radiation

Environments with high levels of ionizing radiation create special design challenges. A single charged particle can knock thousands of electrons loose, causing electronic noise and signal spikes. In the case of digital circuits, this can cause results which are inaccurate or unintelligible. This is a particularly serious problem in the design of satellites, spacecraft, military aircraft, nuclear power stations, and nuclear weapons. In order to ensure the proper operation of such systems, manufacturers of integrated circuits and sensors intended for the military or aerospace markets employ various methods of radiation hardening. The resulting systems are said to be rad(iation)-hardened, rad-hard, or (within context) hardened.

Major radiation damage sources

Typical sources of exposure of electronics to ionizing radiation are the Van Allen radiation belts for satellites, nuclear reactors in power plants for sensors and control circuits, particle accelerators for control electronics particularly particle detector devices, residual radiation from isotopes in chip packaging materials, cosmic radiation for spacecraft and high-altitude aircraft, and nuclear explosions for potentially all military and civilian electronics.

Radiation effects on electronics

Fundamental mechanisms

Two fundamental damage mechanisms take place:

The effects can vary wildly depending on all the parameters – type of radiation, total dose and radiation flux, combination of types of radiation, and even the kind of device load (operating frequency, operating voltage, actual state of the transistor during the instant it is struck by the particle) – which makes thorough testing difficult, time consuming, and requiring a lot of test samples.

Resultant effects

The "end-user" effects can be characterized in several groups:

Digital damage: SEE

Single-event effects (SEE), mostly affecting only digital devices, were not studied extensively until relatively recently. When a high-energy particle travels through a semiconductor, it leaves an ionized track behind. This ionization may cause a highly localized effect similar to the transient dose one - a benign glitch in output, a less benign bit flip in memory or a register or, especially in high-power transistors, a destructive latchup and burnout. Single event effects have importance for electronics in satellites, aircraft, and other civilian and military aerospace applications. Sometimes, in circuits not involving latches, it is helpful to introduce RC time constant circuits that slow down the circuit's reaction time beyond the duration of an SEE.

SEE testing

While proton beams are widely used for SEE testing due to availability, at lower energies proton irradiation can often underestimate SEE susceptibility. Furthermore, proton beams expose devices to risk of total ionizing dose (TID) failure which can cloud proton testing results or result in pre-mature device failure. White neutron beams — ostensibly the most representative SEE test method — are usually derived from solid target-based sources, resulting in flux non-uniformity and small beam areas. White neutron beams also have some measure of uncertainty in their energy spectrum, often with high thermal neutron content.

The disadvantages of both proton and spallation neutron sources can be avoided by using mono-energetic 14 MeV neutrons for SEE testing. A potential concern is that mono-energetic neutron-induced single event effects will not accurately represent the real-world effects of broad-spectrum atmospheric neutrons. However, recent studies have indicated that, to the contrary, mono-energetic neutrons—particularly 14 MeV neutrons—can be used to quite accurately understand SEE cross-sections in modern microelectronics.

A particular study of interest, performed in 2010 by Normand and Dominik,[2] powerfully demonstrates the effectiveness of 14 MeV neutrons.

The first devoted SEE testing laboratory in Canada is currently being established in Southern Ontario under the name RE-Labs Inc..

Radiation-hardening techniques

Radiation hardened die of the 1886VE10 microcontroller prior to metalization etching
Radiation hardened die of the 1886VE10 microcontroller after a metalization etching process has been used

Military and space industry applications

Radiation-hardened and radiation tolerant components are often used in military and space applications. These applications may include:

Nuclear hardness for telecommunication

In telecommunication, the term nuclear hardness has the following meanings:

  1. An expression of the extent to which the performance of a system, facility, or device is expected to degrade in a given nuclear environment.
  2. The physical attributes of a system or electronic component that will allow survival in an environment that includes nuclear radiation and electromagnetic pulses (EMP).


  1. Nuclear hardness may be expressed in terms of either susceptibility or vulnerability.
  2. The extent of expected performance degradation (e.g., outage time, data lost, and equipment damage) must be defined or specified. The environment (e.g., radiation levels, overpressure, peak velocities, energy absorbed, and electrical stress) must be defined or specified.
  3. The physical attributes of a system or component that will allow a defined degree of survivability in a given environment created by a nuclear weapon.
  4. Nuclear hardness is determined for specified or actual quantified environmental conditions and physical parameters, such as peak radiation levels, overpressure, velocities, energy absorbed, and electrical stress. It is achieved through design specifications and it is verified by test and analysis techniques.

Examples of rad-hard computers

See also


  1. "Radiation Hardening" McGraws AccessScience
  2. E. Normand and L. Dominik. "Cross Comparison Guide for Results of Neutron SEE Testing of Microelectronics Applicable to Avionics," 2010
  3. 1 2 Leppälä, Kari; Verkasalo, Raimo (1989). "Protection of Instrument Control Computers against Soft and Hard Errors and Cosmic Ray Effects". CiteSeerX accessible.
  4. Platteter, D.G. (October 1980). Protection of LSI Microprocessors using Triple Modular Redundancy. International IEEE Symposium on Fault Tolerant Computing.
  5. Krishnamohan, Srivathsan; Mahapatra, Nihar R. (2005). "Analysis and design of soft-error hardened latches". Proceedings of the 15th ACM Great Lakes symposium on VLSI. GLSVLSI '05.

Books and Reports

External links

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