Larry, there is at least one other company that appears to have superior technology to the spinvalves, TMJs, and Hitachi's double transistor (PLEDM, non-volatile?) memory cells. Energy Conversion Devices (ENER) uses only a controllable resistor as a memory element. The whole memory cell is just the usual transistor plus a tiny area of resistance material that can be written and read through the same two wires - a very simple, totally planar structure. This is claimed to be the "ideal" memory element, and it IS hard to imagine anything much simpler than a resistor. The resistance of the element is controllable to 16 levels or more. They claim speeds down to 1 ns are possible, and the memory elements are non-volatile virtually forever.
The resistors are made of the same material used for the DVD disks (also, the CD-RW disks, etc.) that are expected to dominate the removable disk storage arena. The material changes its crystalline structure, and thus its resistivity, under lazer heating (for the disks) as well as electronic current for (memory chips). ECD has licensed this "phase change" technology to optical disk makers throughout the world, and they have acquired Tyler Lowery (a MAJOR talent, from Micron) to put the memory chips into production.
The resistive memory elements work BETTER as they are scaled down, limited only by lithographic techniques, and the processing is compatible with existing chip making methods. An interesting "slide show" on these memory elements is presented at ECD's web site (WWW.Ovonic.com). |
