Browsing by Author "Lin, Wei-Liang"

Now showing 1 - 2 of 2

Grain Boundary Trap-Induced Current Transient in a 3-D NAND Flash Cell String
(2019-04-01)
Lin, Wei-Liang
;
Tsai, Wen-Jer
;
Cheng, C. C.
;
Ku, S. H.
;
Liu, Lenvis
Transient cell current caused by the trapping/detrapping of grain boundary traps in the polycrystalline silicon (poly-Si) channel of a 3-D NAND cell string is comprehensively studied in this paper. This transient has a time constant of 10 mu s or longer and is strongly dependent on the bias history. It is also affected by the trap distribution as revealed by TCAD simulations. Sensing offset between program verify and read results in "pseudo" charge loss/gain that reduces the sensing margin. The posttreatment of the poly-Si channel is suggested to mitigate this effect.
Hot-Carrier Injection-Induced Disturb and Improvement Methods in 3D NAND Flash Memory
(2019-01-01)
Lin, Wei-Liang
;
Tsai, Wen-Jer
;
Cheng, C. C.
;
Lu, Chun-Chang
;
Ku, S. H.
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.