Testing static and dynamic faults in random access memories

The ever increasing trend to reduce DPM levels of memories requires tests with very high fault coverage. The important class of dynamic faults, therefore, cannot be ignored any more. It is shown that conventional memory tests constructed to detect static faulty behavior of a specific defect do not necessarily detect the dynamic faulty behavior. Indeed, dynamic faulty behavior can take place in the absence of static faults. The paper presents new memory tests derived to target the dynamic fault class.