US Patent 7340356 - Nanowire crossbar readout using resistance enhancing biasing

http://www.freepatentsonline.com/7340356.html

RRAM is a non-volatile memory type that works based on the storage of data in the form of high or low resistance states instead of by storing charge as in flash memory. Hewlett-Packard is using rotaxane molecules between intersecting nanowires to form a nanowire crossbar RRAM memory however one of the problems is that the high or low resistance states of different crosspoints can be inconsistent during a read out operation. This patent teaches a method and system of increasing the resistance states of crossbar junctions to make read out easier. Claim 1 reads:

1. A method for determining a resistance state of a crossbar junction, the method comprising: biasing a pair of wires interconnected through the crossbar junction to determine a first signal level transmitted through the crossbar junction after biasing the pair of wires; biasing the pair of wires interconnected through the crossbar junction to increase the resistance of the crossbar junction; biasing the pair of wires interconnected through the crossbar junction to determine a second signal level transmitted through the crossbar junction after biasing the pair of wires; and outputting the resistance state of the crossbar junction based on comparing the first signal level to the second signal level.