Fish & Richardson P.C.
Method for driving semiconductor device and semiconductor device
To read multilevel data from a memory cell having a transistor using silicon and a transistor using an oxide semiconductor, without switching a signal for reading the multilevel data in accordance with the number of the levels of the multilevel data. The potential of the bit line is precharged, the electrical charge of the bit line is discharged via a transistor for writing data, and the potential of the bit line which is changed by the discharging is read as multilevel data. With such a structure, the potential corresponding to data held in a gate of the transistor can be read by only one-time switching of a signal for reading data.
Semiconductor Energy Laboratory Co., Ltd.
H H G H G G H G G G G
H01L H01L G11C H01L G11C G11C H01L G11C G11C G11C G11C
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Yutaka Takahiko Shuhei Hiroki Takanori Kiyoshi
Shionoiri Ishizu Nagatsuka Inoue Matsuzaki Kato