Patent ID: 7352617

Claim:
A nano tube cell comprising: a capacitor whose one terminal is connected to a word line; and a PNPN nano tube switch, which includes a first PNPN diode switch connected forward between a bit line and a bottom electrode of the capacitor, and a second PNPN diode switch connected backward between the bit line and the bottom electrode of the capacitor successively connected in series and divided into two groups each connected in parallel between the bit line and the other terminal of the capacitor, for being selectively switched depending on a voltage applied to the word line and the bit line, wherein the PNPN nano tube switch is switched to read data stored in the capacitor when a first voltage is applied to the word line, and to write data in the capacitor when a second voltage larger than the first voltage is applied to the bit line, wherein the first PNPN diode switch has an upper P-type region connected to the bottom electrode and a lower N-type region connected to the bit line.