Polysilicon resistor stability under voltage stress for safe-operating area characterization

High resistance polysilicon resistors have been characterized by DC and pulsed I-V sweep measurements, resistance vs. temperature, and DC and pulsed voltage stress/measurement cycling. The combination of these measurements along with resistor linearity and electro-migration rules are used to determine the maximum safe-operating area. It is shown that the resistance shifts at high current conditions cannot be explained by electromigration alone, and are instead attributed to migration of dopants, Si, or hydrogen, either singly or in combination, both due to high self-heating. The results are used to create voltage and current checks within SPICE models allowing for robust design at maximum operating conditions. IR-OBIRCH physical analysis was performed and shows asymmetric changes to the resistor head regions.