Reuben George, Cypress
EDN (April 09, 2015)
Soft errors are random, non-recurring change of state or transient in semiconductors due to energetic particles interacting with the silicon. As SRAM process technology scales for improved performance, the reduced voltage and shrinking node capacitance makes the SRAM devices more susceptible to soft errors. Soft errors not only corrupt data, but may also lead to loss of function and system critical failures. Industrial controllers, military equipment, networking systems, medical devices, automotive electronics, servers, handheld devices, and consumer applications are vulnerable to the adverse effects of soft errors. An uncorrected soft error can lead to system failures in mission critical applications, such as, implantable medical devices, and high-end security systems used in military and automotive electronics.
The basis of this article is to explain how soft errors occur and how they can cause damage to critical data stored in semiconductor memories. To this end, the article covers the sources of soft errors and the likelihood of their occurrence. It also explains how they impact individual memory cells (each cell stores 1 bit) and cause them to change state. The article will also explore the various sources of soft errors, with techniques to mitigate their impact – both at process level and system level. Lastly it briefly describes how on-chip error-correcting code (ECC) in memories counters the effects of soft errors.
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