Effects of front-end-of line process variations and defects on retention failure of flash memory: Charge loss/gain mechanism

• Published in: 2015 IEEE International Reliability Physics Symposium pp. 2B.3.1 - 2B.3.4
• Main Authors: Jongwoo Park, Miji Lee, Hanbyul Kang, Wooram Ko, Eunkyeong Choi, Junsik Im, Minwoo Lee, Dohwan Chung, Jinchul Park, Sangchul Shin, Sangwoo Pae
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-04-2015
• Subjects: As+ implantation; charge loss/gain; contact misalignment; dislocation; Failure analysis; Flash memories; Front-end-of line (FEOL); Ions; Mobile communication; mobile ion; oxygen-nitride-oxygen (ONO) layer; Passivation; retention fail; Silicon compounds; SIMS; Stacking; stacking fault; TEM
• ISSN: 1541-7026; 1938-1891
• DOI: 10.1109/IRPS.2015.7112674

Retention fails on flash memory were comprehensively characterized and fault-isolated for the formulation of failure mechanism. Using in-depth TEM and SIMS characterizations based on electrical findings, we found that FEOL process variations such as contact misalignment (spacer encroachment) and defects (ONO instability and stacking fault), result in retention fail of flash memory. In this paper, the failure mechanism of retention fail governed by charge loss/gain in a same cell is explicated and knobs for robust reliability and decent production are proposed from design and process perspectives.