Local and pseudo SELs observed in digital LSIs and their implication to SEL test method

The characteristic nondestructive single-event latchup (SEL) phenomena, "local" and "pseudo" SELs, were identified in complex digital Large Scale Integrations (LSIs) by using a photo-emission microscope. Usually, SELs are detected as an abrupt increase of power supply current. However, it was experimentally demonstrated that the simple method could not give sufficient information to determine if it is a destructive or a nondestructive phenomenon. If the observed SELs can be confirmed as a nondestructive phenomenon with a certain confidence level, a simple circumvention technique can be effectively employed and the chance to utilize attractive commercial devices will be greatly enhanced. The SEL test method to identify this type of LSI was discussed and a new procedure was proposed.