Term of the Moment
Compaq
Definition: NRAM
(NanoRAM) A non-volatile, random access memory technology from Nantero, Inc. that was developed to initially replace flash memory and ultimately RAM. NRAM uses carbon nanotubes for the bit cells, and the 0 or 1 is determined by the tube's physical state: high resistance or grounded.
Spin Coat the Tubes onto the Wafer
Making NRAM cells is unique. A solution of purified carbon nanotubes is placed onto a wafer with predefined round electrodes and spun at centrifugal force to spread the fluid. The tubes wind up in random polarizations, spread evenly across the wafer and over the electrodes. Subsequent steps remove the extraneous tubes and add the interconnects. Each electrode with its carbon tubes becomes a memory cell (see below).
The Bits Are Nanotubes
Making the NRAM Cells
Spin Coat the Tubes onto the Wafer
Making NRAM cells is unique. A solution of purified carbon nanotubes is placed onto a wafer with predefined round electrodes and spun at centrifugal force to spread the fluid. The tubes wind up in random polarizations, spread evenly across the wafer and over the electrodes. Subsequent steps remove the extraneous tubes and add the interconnects. Each electrode with its carbon tubes becomes a memory cell (see below).
A 0 or 1 is determined by whether the tubes are straight or bent. Changing the electrode charge attracts or repels the positively charged nanotube. When straight, the tube has high resistance; when bent down, it has low resistance. The distance between up and down is 1/10,000 the thickness of one human hair.
Only two cells are shown here to illustrate the concept; however, billions of cells are created on a wafer, and many, many more tubes land over each electrode.