Patent attributes
A storage device includes a storage element having first and second terminals that cause a first electrical characteristic change when an electric signal of a first threshold level or higher is applied and that cause a second electrical characteristic change, which is asymmetrical to the first electrical characteristic change, when an electric signal of a second threshold level or higher, the polarity of the electric signal of the second threshold level or higher being different from the polarity of the electric signal of the first threshold level or higher, is applied; and a unipolar transistor connected in series with the storage element. One of the first terminal and the second terminal of the storage element is electrically connected to the unipolar transistor. The unipolar transistor has a negative polarity or a positive polarity in accordance with the first terminal or the second terminal electrically connected to the unipolar transistor.