Now, a memory device that combines nanowires with traditional data-storage technology

American and South Korean Scientists have fabricated a memory device that combines silicon nanowires with a more traditional type of data-storage.

Washington, June 10 : American and South Korean Scientists have fabricated a memory device that combines silicon nanowires with a more traditional type of data-storage.

Researchers say their hybrid structure may be more reliable than other nanowire-based memory devices built recently, and could as well be easily integrated into commercial applications.

According to the scientists, the device is a type of "non-volatile" memory, like flash memory, which is widely used in digital camera memory cards and USB memory sticks, meaning stored information is not lost when the device is without power.

In this new device, nanowires are integrated with a higher-end type of non-volatile memory that is similar to flash, a layered structure known as semiconductor-oxide-nitride-oxide-semiconductor (SONOS) technology.

Applying a positive voltage across the wires causes electrons in the wires to tunnel down into the substrate, charging it.

A negative voltage causes the electrons to tunnel back up into the wires.

This process, the team of scientists from the National Institute of Standards and Technology (NIST), George Mason University, (both US) and Kwangwoon University, Korea report in their paper, is the key to the device's memory function.

"When fully charged, each nanowire device stores a single bit of information, either a "0" or a "1" depending on the position of the electrons. When no voltage is present, the stored information can be read," the researchers write in their study.

According to the study, the nanowires are positioned using a hands-off self-alignment technique, which could also allow the production cost-and therefore the overall cost-of large-scale viable devices to be lower than flash memory cards.

Memory cards, on the other hand, require more complicated fabrication methods.

The scientists say the device combines the excellent electronic properties of nanowires with established technology, thereby making it very promising for applications in non-volatile memory.

"For example, it has simple read, write, and erase capabilities. It boasts a large memory window-the voltage range over which it stores information-which indicates good memory retention and a high resistance to disturbances from outside voltages. The device also has a large on/off current ratio, a property that allows the circuit to clearly distinguish between the "0" and "1" states," the study says.

The research, 'Silicon nanowire on oxide/nitride/oxide for memory application' appears in the journal Nanotechnology.

ANI