A cross section of alpha -particle-induced soft-error phenomena in VLSIs

The alpha -particle-induced soft-error phenomena for VLSIs are investigated using a three-dimensional device simulator and a new experimental method. The scope of the present work includes a description of: the scalability of the funneling length (size effects and proximity effects), the effects of reduced supply voltages, the potential barrier effect of an n⁺-p⁺-p (substrate) structure, compulsory exposure experiments, and a new effect that causes the soft error ( alpha -particle source-drain penetration effect, or ALPEN). A new funneling length behavior that cannot be explained by Hu´s model (1982) is discussed. According to this behavior, it was found that a critical charge for a given soft-error rate, which determines the limitation of planar and trench memory cells, can be scaled down. Furthermore, it is shown that the ALPEN effect, which occurs when an effective channel length of a MOSFET is comparable to the effective funneling length, puts a new constraint on deep submicrometer VLSI design.