THREE-DIMENSIONAL MEMORY ELEMENT AND ITS WRITING-READING METHOD

摘要

PURPOSE:To increase storage capacity by transferring charge without wiring each conducting layer, simplifying element structure, and enabling high degree integration, by a method wherein each threshold voltage for tunnel conduction of electric charge in each tunnel switch film is gradually increased from the 10 electrode side toward the lamination direction of a laminated body. CONSTITUTION:Each of the tunnel switch films 32a-32d is made of same material. The tunnel switch film 32a in contact with an I/O electrode 31a is the thinnest. In accordance with the distance of the film from the I/O electrode 31a, the film thickness is increased. That is, as to the tunnel switch films 32a-32d, the threshold voltage for tunnel conduction of charge is set so as to become higher as the interval between the film and the I/O electrode 31a becomes larger. A writing pulse is applied to the charge input terminal 35 of a writing circuit 33. A reading circuit 34 is constituted of a reading pulse applying terminal 36, a reading capacitor Cd in which read charge is stored, and a charge reading terminal 37.