Modeling of Endurance Degradation and Hard Breakdown for MRAM-OTP Demonstration
Jiongzhe Su, Quanhai Zhu, Yaoru Hou, Qiming Shao, Bo Liu, Hao Cai
Abstract
The Spin-Transfer-Torque Magnetic-Random-Access-Memory (STT-MRAM) has inherent advantages as a One-Time-Programmable (OTP) memory. The Magnetic Tunnel Junction (MTJ) are particularly susceptible to breakdown effect. We also need to reduce the endurance degradation effects during normal write process of MRAM. In this paper, we propose twin progressive models of MTJ breakdown. The endurance degradation model evaluates the trade-off between MTJ endurance and write error rate (WER), while the breakdown time distribution model corrects theoretical MTJ hard breakdown probabilities. The twin models leverage MTJ Time-Dependent-Dielectric-Breakdown (TDDB) and hard breakdown measurement data. The 4-Mb STT-MRAM sub-system was successfully demonstrated using our twin progressive models for reliability-aware design.