FIG. 33 illustrates part of a cross-sectional structure of the memory device 300 in the case where the transistor 100 is used as the transistor 262 of the memory circuit 310 and the transistor 200C is used as the transistor 323 of the voltage retention circuit 320.
In FIG. 33, the memory device 300 includes the transistor 262 and the transistor 323 over the substrate 101 with the insulating layers 102 and 103 provided therebetween; the insulating layer 115 and the insulating layer 439 over the transistors 262 and 323; the electrode 241, an electrode 244, and the electrode 427 over the insulating layer 439; the insulating layer 242 covering the electrodes 241, 244, and 427; and the electrode 243 covering the electrode 241 and an electrode 245 covering the electrode 244 over the insulating layer 242.
A region where the electrode 241, the insulating layer 242, and the electrode 243 overlap with each other functions as the capacitor 258. By providing the electrode 243 to cover the electrode 241, not only a top surface but also side surfaces of the electrode 241 can function as the capacitor. A region where the electrode 244, the insulating layer 242, and the electrode 245 overlap with each other functions as the capacitor 324. By providing the electrode 245 to cover the electrode 244, not only a top surface but also side surfaces of the electrode 244 can function as the capacitor.
