US Patent 7781862 - Nanotube RRAM

http://ip.com/patent/US7781862

Nantero's original concept of non-volatile memory involved electromechanical switches formed from nanotube ribbons. This patent teaches an alternative variation of non-volatile memory formed from immobile nanotube fabrics sandwiched between electrodes which act as programmable fuses or anti-fuses. Claim 1 reads:

1. A two terminal switching device, comprising:

a first conductive terminal;

a second conductive terminal in spaced relation to the first conductive terminal;

a nanotube article having a plurality of nanotubes, said nanotube article being arranged such that the nanotube article is in permanent and direct physical contact with both the first and second conductive terminals; and

stimulus circuitry in electrical communication with at least one of the first and second conductive terminals, said stimulus circuitry configured to create a first voltage difference between the first conductive terminal and the second conductive terminal, to induce a change in the resistance of the nanotube article between the first and second conductive terminals from a relatively low resistance to a relatively high resistance, said stimulus circuitry configured to create a second voltage difference between the first conductive terminal and the second conductive terminal, to induce a change in the resistance of the nanotube article between the first and second conductive terminals from a relatively high resistance to a relatively low resistance, wherein the relatively high resistance of the nanotube article between the first and second conductive terminals corresponds to a first state of the two terminal switching device, and wherein the relatively low resistance of the nanotube article between the first and second conductive terminals corresponds to a second state of the two terminal switching device, wherein the first and second states of the two terminal switching device are nonvolatile.