A Versatile One-Time-Programmable STT-MRAM for Security-Aware Scenario

Recently, one-time-programmable (OTP) memory has been widely used in micro controller unit (MCU) due to its storage reliability and tamper-proof. Based on the analysis of the breakdown mechanism of magnetic tunnel junction and the measurement results used for modeling, this article demonstrates a 96-Kb versatile MRAM-OTP macro integrated with a 6-Kb OTP-based physical unclonable function (PUF) in 55-nm fully depleted silicon on insulator process. The MRAM-OTP macro realize minimum 3.0 V program voltage and 100 ns for 32-bit program speed. The on-chip power supply method trims with PVT variations and completes voltage switching between two modes. The multi-bit programming design saves about 97% time and 5% energy using self-termination. The discernible dual-mode sense amplifier saves 57.4% power in OTP reading with no lacks of sensing yield. We also presented the application scheme of the proposed MRAM-OTP macro within the trimming information storage and security MCU design, with the PUF helped to complete the authentication process together with OTP and the error correcting code assisted encrypting and correcting process. The trimming information can help to enhance the reliability of STT-MRAM main area. With the reconfigurable bit-cell design, the Inter-HD and Intra-HD of the OTP-based PUF can reach 49.77% and 0.08%, respectively.