Origins and Signatures of Tail Bit Failures in Ultrathin MgO Based STT-MRAM
- Resource Type
- Conference
- Authors
- Lim, J. H.; Raghavan, N.; Kwon, J. H.; Lee, T. Y.; Chao, R.; Chung, N. L.; Yamane, K.; Thiyagarajah, N.; Naik, V. B.; Pey, K. L.
- Source
- 2020 IEEE International Reliability Physics Symposium (IRPS) Reliability Physics Symposium (IRPS), 2020 IEEE International. :1-5 Apr, 2020
- Subject
- Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Engineering Profession
Photonics and Electrooptics
Transportation
Degradation
Breakdown voltage
Production
Dielectrics
Dielectric breakdown
Reliability
Junctions
Magnetic tunnel junction
MgO
Pulsed voltage endurance
Time-dependent dielectric breakdown
Tail bit
- Language
- ISSN
- 1938-1891
In this study, the time-dependent dielectric breakdown (TDDB) phenomenon has been investigated in a macro array of nominally identical ultrathin MgO based magnetic tunnel junction (MTJ) devices by bipolar pulsed voltage endurance test. The first of such comprehensive study shows that the MTJ breakdown distribution can be differentiated into stress-induced and process-induced (tail bit) failures. Three unique signatures are observed from the tail bit (TB) failed devices which are attributed to pinhole formation due to interface roughness (TB-1), sidewall redeposition (TB-2) and unintended back hopping (TB-3). We propose the bimodal clustering model to best describe breakdown statistics accounting for the unique TB patterns and localized degradation events. Approaches to resolve these TB failure modes to achieve endurance failure rate < 1ppm after 1M cycles in 40Mb embedded-MRAM product are also presented.