Stability test for silicon on insulator SRAM memory cells utilizing bitline precharge stress operations to stress memory cells under test

摘要

An apparatus, program product, and method of testing a silicon-on-insulator (SOI) static random access memory (SRAM) introduce switching history effects to a memory cell during testing to stress the memory cell such that a reliable determination of stability may be made. Stress is applied to a memory cell through the use of a bitline precharge stress operation, which utilizes the bitline pairs coupled to a memory cell to attempt to flood the memory cell with charge and thereby attempt to cause the memory cell to unexpectedly switch state. The bitline precharge stress operation is performed immediately after the memory cell has been switched to one state after being maintained in an opposite state for a length of time that is sufficient to introduce switching history effects to the memory cell. While a bitline precharge operation may be implemented separate from any write operation, the bitline precharge stress operation may also be incorporated into a write operation through delaying the deassertion of the wordline that occurs in a conventional write operation until after initiation of the bitline precharge operation that conventionally occurs near the end of such a write operation.