| 摘要 |
<p>PURPOSE:To obtain an excellent redundant circuit for ROM circuit without changing a process by providing a gate potential control circuit in order to relieve the defective bits of the ROM circuit with an exactly same structure of a redundant memory cell. CONSTITUTION:A word line potential control circuit is set between a word line 30 connected to a gate of a memory cell transistor TR of a redundant memory cell and an address decoder 28. If a fuse 25 or the word line potential control circuit is cut, the word line potential is set at an H level and the TR whose line 30 is connected to the gate is always kept turned on. Then this TR is actuated as if a depression type transistor existed. When the fuse 25 is not cut in the word line potential control circuit, the output of the line 30 is decided in response to the output of the decoder 28. Then a TR whose line 30 is connected to a gate is actuated as an enhancement type one. As a result, data can be stored in a redundant circuit of a ROM.</p> |
