| 摘要 |
PURPOSE: A reservoir capacitor formed in a guard ring is provided to reduce a dimension of a memory device by excluding a separate space for a reservoir capacitor. CONSTITUTION: A reservoir capacitor includes a guard ring(24), a gate(31), and a gate contact(32). The guard ring surrounds a circuit block which controls an operation of a memory device. The gate is formed on a top part of the guard ring. The gate contact provides a bias to the gate. A well contact(27) for providing the bias is formed in the guard ring. The guard ring is made of dopant of the same type as an active region. An oxide film is formed between the guard ring and the gate.
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