摘要 |
A content addressable memory has many elements in one memory cell; thus, the area of one memory cell tends to be large. In view of the above, it is an object of an embodiment of the present invention to reduce the area of one memory cell. Charge can be held with the use of a channel capacitance in a reading transistor (capacitance between a gate electrode and a channel formation region). In other words, the reading transistor also serves as a charge storage transistor. One of a source and a drain of a charge supply transistor is electrically connected to a gate of the reading and charge storage transistor. |