摘要:
A spare memory cell comprises a read FET (Field Effect Transistor), a fusing FET and a current fuse. The FETs are connected in series between a read data line and a low voltage source. The fuse is inserted between a series node of the FETs and a write data line. The fuse is molten when data is written to the spare memory cell. By applying a power source voltage to a control electrode of the fusing FET and by applying a voltage that is higher than the power source voltage to the write data line, the fusing FET is set to its secondary breakdown state. Under this state, a large current flows through the fusing FET to cut off the fuse, thus writing data to the spare memory cell.