US Patent 7479654 - Nanotube RRAM

http://www.freepatentsonline.com/7479654.html

The research into a variety of new materials in the last decade have resulted in potential for RRAM as a new form of non-volatile memory using resistance as a bit storage element. This patent from Nantero teaches an RRAM memory array based on their nanotube ribbon switches. Claim 22 reads:

22. A memory cell, comprising:

a cell selection circuit in electrical communication with a bit line and a first word line to select the memory cell in response to activation of at least one of the bit line and the first word line; and

a two-terminal nanotube switching device having only first and second conductive terminals to access and program the switching device wherein each of the first and second conductive terminals is coupled to a nanotube article, the first terminal in electrical communication with the cell selection circuit and the second terminal in electrical communication with a second word line,

wherein selecting the memory cell and applying a first electrical stimulus to at least one of the bit line, first word line, and second word line changes a resistance of the switching device between the first and second terminals from a relatively low resistance to a relatively high resistance, and

wherein selecting the memory cell and applying a second electrical stimulus to at least one of the bit line, first word line, and second word line changes a resistance of the switching device between the first and second terminals from a relatively high resistance to a relatively low resistance,

wherein the relatively high resistance between the first and second terminals corresponds to a first informational state of the memory cell, and wherein the relatively low resistance between the first and second terminals corresponds to a second informational state of the memory cell.