Integrated Circuit Design for Radiation Environments

Glossary of Terms

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alpha particle

An alpha particle is a helium nucleus (α) consisting of two protons and two neutrons bound into a particle identical to a helium nucleus. The alpha particle is generally produced during the process of alpha decay of radioactive material, however, alpha particles can also be produced by a silicon nucleus spallation event that is an inelastic collision of a natural cosmic particle (neutron) and the silicon nucleus. Alpha particles emitted from spallation events are energetic and can cause soft errors in silicon devices. As a proton carries one unit of charge, the alpha particle is doubly ionized. In CMOS silicon devices the figure of merit relating natural neutron flux (sensitivity to failure) is the FIT (failure in time). FIT reference is used to quantify the number of single bit failures of a silicon device located at other altitudes to a reference altitude (sea level at New York City in time). FIT units are the number of bit failures per 1 billion neutron particles/cm² passing through the silicon device.

analog design

The design of continuous time circuitry in which data values are expressed as voltage or current levels. This is in contrast with digital circuitry, in which data values are expressed in binary format.

application specific integrated circuit (ASIC)

An integrated circuit that is designed and tested for a specific, narrowly defined application in a subsystem or system. An ASIC is typically not readily suited for ...