A metal-insulator-metal (MIM) capacitor and a process of forming the same are disclosed. The process includes steps of: forming a lower electrode that provides a lower layer and an upper layer; forming an opening in the upper layer; forming a supplemental layer on the lower layer exposed in the opening; heat treating the lower electrode and the supplemental layer; covering at least the upper layer of the lower electrode with an insulating film; and forming an upper electrode in an area on the insulating film, where the area is not overlapped with the supplemental layer and within 100 μm at most from the supplemental layer. A feature of the MIM capacitor is that the supplemental layer is made of a same metal as a metal contained in the lower layer of the lower electrode.