A device includes a substrate, a first zirconium-containing oxide layer, a first metal oxide layer and a top electrode. The first zirconium-containing oxide layer is over a substrate and having ferroelectricity or antiferroelectricity. The first metal oxide layer is in contact with the first zirconium-containing oxide layer. The first metal oxide layer has a thickness less than a thickness of the first zirconium-containing oxide layer. The top electrode is over the first zirconium-containing oxide layer.