ABSTRACT
Ionizing radiation, such as alpha particles, cosmic rays and some types of X-rays, can all cause soft errors. The "soft error," is a random, non-recurring, single event and is different from the permanent "hard" damage caused by other failure mechanisms, including radiation-induced latchup or threshold drift. The soft error rate is then a function of the alpha particle flux, the solid angle described by the geometric relation between the ionization source and visible silicon area, and the sensitivity of the devices in the visible area. The soft error rate can be managed by either reducing circuit sensitivity to current pulses, or reducing the critical flux of ionizing radiation. There are several ways of accomplishing this, and some or all of these are routinely used: reduction of circuit sensitivity through chip design and process, reduction of ionizing flux through material control, packaging process, and package design.
