Processor-Based Built-in Self-Optimizer for 90nm Diode-Switch PRAM

A PRAM includes 8 b embedded RISC to generate the optimized internal timing and voltage parameters to control the variations of the cell resistances. The PRAM blocks with small margin window of cell resistances are detected, analyzed and controlled by processor-based built-in self-optimizer (BISO). A 4 Mb test PRAM is fabricated in a 90 nm 3-metal diode-switch PRAM cell technology. Measured margin increases by up to 221%.