US Patent 7378870 - Symmetrical resistance switching crossbar array

http://www.freepatentsonline.com/7378870.html

In order to create higher density non-volatile memory designs there has been increased interest in RRAM designs which employ materials which can be programmed to have high or low resistance states based on an applied voltage. Hewlett-Packard and Nantero have extended such designs to the nanoscale using molecular materials such as rotaxane molecules (HP) or carbon nanotube ribbons (Nantero). This is one of my patents covering a symmetrical crossbar structure in which reversal of the switching between the high and low conductivity states can be more easily achieved. For licensing information go to this link. Claim 1 reads:

1. A device comprising:

a first crossbar section including a rectifying layer having a first side and a second side, a first array of wires formed above the first side of the rectifying layer, and a second array of wires formed below the second side of the rectifying layer;

a second crossbar section including a symmetrical structure to the first crossbar section; and

a programmable material layer between the first crossbar section and the second crossbar section.