Hamid Choukri, Gemplus & University of Bordeaux, France
Michael Tunstall, Gemplus & Royal Holloway, University of London
One of the first examples of faults being injected in a microchip was accidental. It was noticed that radioactive particles produced by elements present in the packaging material (May & Woods, 1978) caused faults in chips. Uranium-235, Uranium-238, and Thorium-230 was present that decays to Lead-206. The process released alpha particles that created a charge in sensitive areas of the chip causing bits to flip. These elements were only present in 2 or 3 parts per million, but this was sufficient to have an effect on the behavior of the chip.
Subsequent research included studying the effects of cosmic rays on semiconductors (Ziegler, 1979). Cosmic rays are weak at ground level because of the earth's atmosphere. The probability of a fault produced in an integrated circuit is therefore very small, but the more random access memory (RAM) a computer has, the higher the chance of a fault occurring (i.e., it becomes more likely that ...