Nano tube cell, and semiconductor device having nano tube cell and double bit line sensing structure
View Patent ↗The present invention discloses a nano tube cell, and a semiconductor device having the nano tube cell and a double bit line sensing structure. The cell array circuit includes a plurality of top sub cell arrays, a plurality of bottom sub cell arrays, a main bit line sense amp and a word line driving unit. Especially, the top and bottom sub cell arrays have a double bit line sensing structure for inducing a sensing voltage of a main bit line by controlling a volume of a current supplied from a power voltage to the main bit line according to a sensing voltage of a sub bit line receiving a cell data. Each of the sub cell arrays includes a capacitor, and a PNPN nano tube cell having a PNPN diode switch selectively turned on/off according to a voltage difference between one side terminal of the capacitor and the sub bit line, to decrease a cell size and improve operational characteristics of the circuit.
1. A nano tube cell, comprising:
a capacitor for storing cell charges corresponding to a cell data, and having a first electrode of which being coupled to a word line;
a first PNPN tube coupled between a second electrode of the capacitor and a bit line, and turned on when a voltage of the bit line is higher than that of the second electrode by a predetermined level, for enabling a current to flow from the bit line to the capacitor; and
a second PNPN tube coupled between the second electrode and the bit line, and turned on when the voltage of the second electrode is higher than that of the bit line by a predetermined level, for enabling the current to flow from the capacitor to the bit line.
2. The nano tube cell of claim 1 , wherein the first PNPN tube is a PNPN diode coupled between the second electrode and the bit line in the backward direction, and
wherein the second PNPN tube is a PNPN diode coupled between the second electrode and the bit line in the forward direction.
3. The nano tube cell of claim 2 , wherein the PNPN diodes composing the first PNPN tube and the second PNPN tube are connected in series in the orthogonal direction to the word line, for forming a serial PNPN tube chain.
4. The nano tube cell of claim 3 , wherein the capacitor is formed in a cross region of the serial PNPN tube chain and the word line.
5. The nano tube cell of claim 4 , wherein the capacitor comprises:
a bottom electrode stacked above the serial PNPN tube chain in a column shape to be commonly connected to a N terminal positioned in the end of the first PNPN tube and a P terminal positioned in the end of the second PNPN tube through a contact node;
a dielectric film stacked on the surface of the bottom electrode; and
a top electrode stacked on the surface of the dielectric film and coupled to the word line.