the most common is to harden for total-ionizing-dose
radiation — or the amount of radiation the device is
expected to withstand for its entire life before problems
occur. A typical requirement is for 100 kilorads of total-dose radiation hardness.
The evolution of today’s advanced electronic components, however, also is changing the total-dose picture.
Specifically, the shrinking size of circuits on today’s
most modern chips is lessening their vulnerability to
“As technology nodes decrease in size — from 90
nanometers to 14 nanometers — total ionizing dose performance naturally improves,” says Michelle Mundie,
business area director of standard products at rad-hard
specialist Cobham Semiconductor Solutions in Colorado
This phenomenon is a double-edge sword, however,
because the steady shrinking of chip geometries also
makes these devices even more vulnerable to other
kinds of radiation effects, namely single-event upset
(SEU) and single-event latchup (SEL). “Single-vent effects
like latchup are becoming more of a problem, so we
have to design for those effects,” Mundie says. “Devices
today are more sensitive to radiation at the gate and
Single-event upset can corrupt data when a radia-
tion-charged particle flips a data bit from a one to a
zero, or vice versa, which corrupts data. SEU typically
does not physically damage an electronic device, only
the data it contains or that flows through it. Single-
event latchup, however, can be damaging if it causes
a short circuit that triggers thermal runaway. Device
designers must consider these potential threats.
There are several design approaches to mitigating radiation effects, which include radiation hardening by design, selective shielding, redundancy, and
error-checking. One of today’s most notable rad-hard
by design projects is the High Performance Spaceflight
Computing (HPSC) Processor Chiplet program.
Rad-hard by design
Rad-hard by design involves designing an electronic component from the ground up to resist radiation effects. It can be one of the most expensive and
time-consuming approaches, but sometimes it’s the
only solution for electronic components that are crucial
for protecting human lives or safeguarding important
orbital and deep-space missions.
U.S. government space experts are working with the
Boeing Co. to create a new generation of radiation-hardened microprocessors for a wide variety of space applications to provide some of the most advanced processor
Curtiss-Wright is providing the company’s radiation-tolerant Smart
Backplane technology for the European Space Agency’s Vega-C
expendable space launch rocket.