An Extended Temperature Range ePCM Memory in 90-nm BCD for Smart Power Applications

This paper presents a temperature-robust embedded Phase-Change Memory (ePCM) with high cycling capability able to meet all the stringent specifications coming from the automotive environment and, more specifically, the used phase-change material (based on Ge-rich GST alloy) has been tuned to fit power ICs constraints. In order, to cope with the -40 degrees C to 175 degrees C operation requirements, a temperature-compensated write algorithm was conceived and specific circuits were added to render the statistical distribution of programming pulses equal at any temperature as it is required to obtain a uniform ageing of the cells thus ensuring an higher reliability after 100k cycling. Programming operation was optimized thanks to an improved program load that has been designed to compensate for the expected large power supply variations. Experimental characterization demonstrated a 16 ns access time over the whole temperature range.