A boost circuit is used to provide boosting voltage to a common boost node of a plurality of sub-word line drivers in memory systems and devices. The boost circuit includes a Metal Insulator Metal Capacitor. By using the boost circuit, the plurality of sub-word line drivers are configured to output a certain voltage to local word lines without using high DC generators to generate high voltages (4.2 volts or more). The area of the semiconductor substrate used for fabricating the sub-word line drivers is reduced, and thus reduce the cost or increasing the capacity of the memory devices.