METHOD FOR DRIVING SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE

摘要

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 electrical charge of a bit line is discharged, the potential of the bit line is charged via a transistor for writing data, and the potential of the bit line which is changed by the charging 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.

主权项

1. A method for driving a semiconductor device comprising a memory cell, wherein the memory cell comprises a first transistor, a second transistor and a third transistor, wherein one of a source and a drain of the first transistor is electrically connected to a gate of the second transistor, wherein the other of the source and the drain of the first transistor is electrically connected to a bit line, wherein one of a source and a drain of the second transistor is electrically connected to one of a source and a drain of the third transistor, wherein the other of the source and the drain of the third transistor is electrically connected to the bit line, and wherein the second transistor is an n-channel transistor, the method comprising the steps of:
writing data to the memory cell by turning on the first transistor; and reading the data from the memory cell by turning on the third transistor and charging a potential of the bit line.