US 11,699,486 B2
Semiconductor memory device to hold 5-bits of data per memory cell
Tomonori Takahashi, Yokohama (JP); Masanobu Shirakawa, Chigasaki (JP); Osamu Torii, Tokyo (JP); and Marie Takada, Yokohama (JP)
Assigned to KIOXIA CORPORATION, Tokyo (JP)
Filed by KIOXIA CORPORATION, Tokyo (JP)
Filed on May 6, 2022, as Appl. No. 17/738,069.
Application 17/738,069 is a continuation of application No. 17/143,530, filed on Jan. 7, 2021, granted, now 11,361,820.
Application 17/143,530 is a continuation of application No. 16/564,279, filed on Sep. 9, 2019, granted, now 10,923,186, issued on Feb. 16, 2021.
Claims priority of application No. 2019-054177 (JP), filed on Mar. 22, 2019.
Prior Publication US 2022/0270678 A1, Aug. 25, 2022
Int. Cl. G11C 11/56 (2006.01); G11C 16/26 (2006.01); G11C 16/08 (2006.01); G11C 16/04 (2006.01)
CPC G11C 11/5671 (2013.01) [G11C 16/0483 (2013.01); G11C 16/08 (2013.01); G11C 16/26 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A semiconductor memory device comprising:
a memory cell configured to hold 5-bit data according to a threshold;
a word line coupled to the memory cell; and
a row decoder configured to apply first to 31st voltages to the word line,
wherein a first bit data of the 5-bit data is determined by reading operations using first to sixth voltages,
a second bit data of the 5-bit data is determined by reading operations using seventh to thirteenth voltages, the second bit being different from the first bit,
a third bit data of the 5-bit data is determined by reading operations using fourteenth to twentieth voltages, the third bit being different from the first and second bits,
a fourth bit data of the 5-bit data is determined by reading operations using 21st to 27th voltages, the fourth bit being different from the first to third bits,
a fifth bit data of the 5-bit data is determined by reading operations using 28th to 31st voltages, the fifth bit being different from the first to fourth bits,
the first to 31st voltages are respectively different voltages,
the 28th voltage is the lowest voltage among the first to 31st voltages,
the 31st voltage is the highest voltage among the first to 31st voltages,
the first voltage is a second lowest voltage among the first to 31st voltages,
the 27th voltage is a second highest voltage among the first to 31st voltages,
the twentieth voltage a third highest voltage among the first to 31st voltages,
the sixth voltage is highest among the first to sixth voltages,
the thirteenth voltage is highest among the seventh to thirteenth voltages,
the twentieth voltage is highest among the fourteenth to twentieth voltages,
the 27th voltage is highest among the 21st to 27th voltages,
the 31st voltage is highest among the 28th to 31st voltages,
the sixth voltage is lowest among the sixth voltage, the thirteenth voltage, the twentieth voltage, the 27th voltage, and the 31st voltage,
the seventh voltage is lowest among the seventh to thirteenth voltages,
the fourteenth voltage is lowest among the fourteenth to twentieth voltages,
the 21st voltage is lowest among the 21st to 27th voltages,
the 28th voltage is lowest among the 28th to 31st voltages, and
the 21st voltage is highest among the first voltage, the seventh voltage, the fourteenth voltage, the 21st voltage, and the 28th voltage.