Tech Shout!

Scientists who work for IBM, Qimonda and Macronix have announced the results of a joint research that was undertaken by them. The research covered a new type of computer memory which may have the potential to be the next best thing after flash memory chips that are widely used in computers as well as consumer electronics like digital cameras and portable music players.

The scientists from IBM, Qimonda and Macronix worked together at the IBM Research labs on both U.S coats, where they designed, built and demonstrated a prototype phase-change memory device that switched more than 500 times faster than flash memory chips. Besides, the phase-change memory device used less than half the power to write data into a cell.

The “phase-change” device has a cross-section that is a as small as 3 by 20 nanometers in size, making it much much smaller than flash memory chips which are used in todays times. Using Moore’s Law advancements, the new results have shown that unlike flash memory chips, phase-change memory technology can be improved as it gets smaller in size.

The new material that is used for the phase-change technology is a complex semiconductor allow that has been created in a thorough search conducted at IBM’s Almaden Research Center in San Jose, Calif. The complex semiconductor alloy was designed with the help of mathematical simulations.

It is known that a computer memory cell stores information i.e. a digital “zero” or “one”, in a structure that can be switched rapidly between two different states. In fact, most memories today are actually based on the presence or absence of electrical charge that is contained in a small confined region of the cell. SRAM is the fastest, while DRAM, the most economical memory designs that use leaky memory cells and hence they must be powered constantly. In fact, in the case of DRAM, the memory cells must be frequently refreshed. Thus you can see that these “volatile” memories, so to say, tend to lose their information whenever their power supply is interrupted.

Most flash memory that is used today has a “floating gate” charge-storing cell that has especially been designed not to leak. Thus flash memory tends to retain its stored data, and would require power only to read, erase or write information. Now, this “non-volatile” trait makes flash memory very beneficial in battery-powered portable electronics. Even in general computer applications, this non-volatile memory would be a great boon.

But, writing data onto flash memory is thousands of times lower than DRAM or even SRAM. Besides, flash memory cells tend to degrade and hence become unreliable after being rewritten about 100,000 times. For personal consumer uses, this may not be a big problem. But when it comes to using flash applications that must be frequently rewritten, such as computer main memories and the buffer memories in networks or storage systems, then there may be problems faced.

Lastly, it may just become very difficult to keep the current cell design of flash memory “non-volatile”, because Moore’s Law shrinks the minimum feature size below 45 nanometers.

The IBM/Qimoda/Macronix project to develop a usable phase-change memory device has proven to be successful, and the technical details of this research will be presented this week at the Institute of Electronics and electrical engineer’s (IEEE’s) 2006 International Electronic Devices Meeting in San Francisco on December 13.