Hot-Carrier Injection-Induced Disturb and Improvement Methods in 3D NAND Flash Memory
Wei-Liang Lin, Wen-Jer Tsai, C. C. Cheng, Chun-Chang Lu, S.H. Ku, Yao-Wen Chang, Guan-Wei Wu, Lenvis Liu, S. W. Hwang, Tao‐Cheng Lu, Kuang‐Chao Chen, Tseung‐Yuen Tseng, Chih-Yuan Lu · 2019
We investigate a hot-carrier injection-induced program disturb in a 3D NAND flash memory. As there exist specific coding patterns, a “down-coupling” region and a “pre-charge” regions are formed during program-verify and the following program phases, respectively, in the inhibit cell strings. A high heating field is built nearby the PGM wordline. Hot carriers may inject into the inhibit cells as Vpgm is applied. Soft ramp-down and pre-turn-on schemes are proposed to mitigate this disturb.