Improving Computer Memory with Nanotechnology
Researchers are using nanotechnology to create other types of computer memory, attempting to leapfrog flash memory that is dominant in today’s marketplace. Various companies and universities are developing four methods of using nanowires or nanoparticles to increase the amount of memory stored on solid-state drives.
Make memory with memristors
Hewett Packard is developing a memory device that uses nanowires coated with titanium dioxide. One group of these nanowires is deposited parallel to another group. When a perpendicular nanowire is laid over a group of parallel wires, a device called a memristor is formed at each intersection.
A memristor can be used as a single-component memory cell in an integrated circuit. By reducing the diameter of the nanowires, researchers believe memristor memory chips can achieve higher memory density than flash memory chips.
Nanowire race tracks
Magnetic nanowires made of an alloy of iron and nickel are being used to create dense memory devices. Researchers at IBM have developed a method to magnetize sections of these nanowires.
By applying a current they can move the magnetized sections along the length of the wire. As the magnetized sections move along the wire, the data is read by a stationary sensor. This method is called race track memory because the data races by the stationary sensor.
The plan is to grow hundreds of millions of U-shaped race track nanowires on a silicon substrate to create low-cost, high-density, and highly reliable memory chips.
Silicon dioxide memory sandwiches
Another method of using nanowires is being investigated at Rice University. Researchers at Rice have found that they can use silicon dioxide nanowires to create memory devices. The nanowire is sandwiched between two electrodes. By applying a voltage, you change the resistance of the nanowire at that location. Each location where the nanowire sits between two electrodes becomes a memory cell.
The key to this approach is that researchers have found that they can repeatedly change the state of each memory cell between conductive and nonconductive without damaging the material’s characteristics. These researchers believe that they can achieve high memory densities by using nanowires with a diameter of about 5 nm and by stacking multiple layers of arrays of these nanowires like a triple-decker club sandwich.
Nanodots to store more data in smaller space
An alternative method being developed to increase the density of memory devices is to store information on magnetic nanoparticles. Researchers at North Carolina State University are growing arrays of magnetic nanoparticles, called nanodots, which are about 6 nm in diameter. Each dot would contain information determined by whether or not they are magnetized. Using billions of these 6-nm diameter dots in a memory device could increase memory density.
It will be interesting to see how these methods, and the work by existing memory manufacturers to improve existing memory storage devices, pan out. Which type of memory devices we’ll be using 5 or 10 years from now will come down to the right mix of memory density, power consumption, data read and write speeds, and which technique attracts the funding to build manufacturing plants.