Operation Scheme Optimizations to Achieve Ultrahigh Endurance (1010) in Flash Memory
Yang Feng, Xinyi Guo, Chengcheng Wang, Yueran Qi, Junyu Zhang, Jing Liu, Xuepeng Zhan, Jixuan Wu, Jiezhi Chen · IEEE Transactions on Electron Devices · 2024
Flash memory has been widely adopted as stand-alone memory and embedded memory due to its robust reliability. However, the limited endurance obstacles its further applications in storage class memory (SCM) and to proceed endurance-required computing-in-memory (CIM) tasks. In this work, the optimization strategies have been studied to tackle this concern. It is shown that by adopting the channel hot electrons injection (CHEI) and hot hole injection (HHI) to implement program/erase (PE) cycling together with a balanced memory window (MW) at the high-Vth (HV) mode, impressively, the endurance can be greatly extended to 1010 PE cycles, which is a record-high value in flash memory. Moreover, by using the proposed electric-field-assisted relaxation (EAR) scheme, the degradation of flash cells can be well suppressed with better subthreshold swings (SS) and lower leakage currents (sub-10 pA after 1010 PE cycles). Our results shed light on the optimization strategy of flash memory to serve as SCM and implement endurance-required CIM tasks.