Memory devices include a first dielectric layer disposed on a substrate. Memory devices include a pair of contacts and a dielectric portion disposed in an opening of the first dielectric layer. The pair of contacts are separated from each other by the dielectric portion. Each contact includes a first conductive portion disposed on the substrate, a second conductive portion disposed over the first conductive portion and a lining layer disposed between the first conductive portion and the second conductive portion and on a sidewall of the opening. The second conductive portion has a sidewall that is in contact with the dielectric portion and the lining layer is not located thereon. The second conductive portion has a corner in connection with the sidewall and a top surface of the second conductive portion, and a protection portion is disposed on the corner.