Measuring and Suppressing Soft Errors in Memory Devices

feifei

Measuring and Suppressing Soft Errors in Memory Devices [Copy link]

Measuring and Suppressing Soft Errors in Memory Devices

Soft errors are " disturbances " ( i.e., data loss ) in semiconductor devices that cannot be intentionally reproduced . They are caused by external factors that are beyond the designer's control, including alpha particles, cosmic rays, and thermal neutrons. Many systems can tolerate some degree of soft errors. For example, if designing a pre-compression capture buffer or a post-decompression playback buffer for an audio, video, or still imaging system, an occasional defective bit may not be noticeable and may not be important to the user. However, when the memory element is responsible for controlling the function of the system in a mission-critical application, the adverse effects of soft errors are much more serious, not only corrupting the data, but also potentially causing loss of functionality and critical system failure. This article will discuss the root causes of these soft errors, different measurement techniques, and methods to mitigate them. The soft error rate (SER) problem gained widespread attention as a memory data topic in the late 1970s when DRAMs began to show signs of random failure. As process geometries continued to shrink, the critical charge required to cause a misalignment decreased much faster than the charge accumulation area in the memory cell. This means that when using smaller process geometries such as 90nm , soft errors are a more significant concern and further steps need to be taken to ensure that the soft error rate is maintained at an acceptable level.