Study On The Retention Of Resistive Random Access Memory (RRAM) Based On The 28 Nm Standard Logic Platform

In recent years,with the popularity and the continuous development of portable electronic products,such as smart phones,digital cameras,tablet computer and removable storage devices,the nonvolatile memory market explosively grow.Flash memory based on charge storage concept is the mainstream products in nonvolatile memory market for more than twenty years.However,flash memory suffers from several obvious disadvantages such as slow program speed(>10?s),poor endurance(<10~6 cycles)and high operating voltage(>10 V).Moreover,flash memory will reach their physical miniaturization limitation in the near future due to deterioration of reliability.It's more and more difficult for flash memory to meet the requirement of the big-data era.Hence,developing emerging nonvolatile memory technology based new storage concept is urgent.Resistance random access memory(RRAM),based on the resistance switching storage concept,has been considered the most promising next-generation nonvolatile memory,due to outstanding memory performances and high compatibility with current conventional CMOS process.With the unremitting efforts of nearly ten years of researchers,RRAM has been rapidly developed and become one of the hot spots in the storage field.However,in order to put a series of mature products of RRAM,there are still some problems that need to be solved,such as the endurance,retention,disturbance characteristic of RRAM.Thus,developing BEOL based NVMs on standard CMOS platform in 28 nm node could be a new start of eNVM evolution in advanced technology node.Thus,retention characteristic,one important issue of the reliability,is invested in this article based on our 1Mb macro chip.Careful evaluation on thermal stability were performed in 1Mb array.The statistic results show both HRS and LRS could survive after long time high temperature baking(150?)and soldering reflow process(260?).At the same time,a method which can improve the retention character has been come up and proved effectively.