The USB drive will exceed its current limitations

Jul 23, 2009 11:00 GMT  ·  By
In a few years, USB drives could include a memory type based on crossbar acrhitecture, rather than on flash memory
   In a few years, USB drives could include a memory type based on crossbar acrhitecture, rather than on flash memory

One of the most widespread types of memory today is the “flash” one, the kind that can be found in the average USB drive. The popular, non-volatile technology is, however, beginning to reach its limits, as efforts to fit more data into smaller devices are becoming increasingly difficult. That's why Italian experts at the Laboratorio Nazionale MDM, in Milan, are currently looking for new architectures to overcome these hurdles. The answer, they believe, lies within “phase change” or “resistive change” materials, which store data by changing their electrical properties, ICT Results reports.

Dr. Grazia Tallarida, the coordinator of the new VERSATILE project for the Laboratorio Nazionale MDM, says of the challenges facing flash drives today that, “Making these devices smaller and also enlarging their capacity is becoming more and more difficult. So there is a lot of work now to find different technologies for non-volatile memories.” Talking about the newly proposed type of memory, the expert adds that, “These are materials in which you store information – zero or one – by changing the electrical properties. They just need a voltage drop across them to be switched between an ‘off’ state and an ‘on’ state.”

What would make such a construct possible, the team reveals, is something known as the “crossbar architecture,” in which memory cells, constructed from chemicals such as nickel oxide, are crammed between two sets of parallel conductors. They have to be placed at a 90-degree angle towards each other, as this layout allows for each of the cells to be turned “on” or “off” individually, by applying the correct voltage.

The innovation that VERSATILE brought to this type of arrangement is hooking up each memory cell to a diode. This eliminates any trace of interference between the cells, and ensures that each of the tiny components is activated only at the system intended for it. The end-result is that the overall performance of the memory does not degrade as cells are constantly activated and deactivated. “The main point is not researching the memory cell itself, but about the crossbar architecture and the diodes that are needed to build the crossbar devices,” Tallarida says.

The complex demands of such a device have even ruled out the use of silicon diodes, which require high temperatures to be formed. As the overall heat level needs to be maintained below 350 degrees Celsius, the experts opted for a solution that involves the use of zinc oxide diodes, which promise to do the job just as well, but at the required temperature. Chip manufacturer Intel and STMicroelectronics are the owners of the industrial partner for the project, Numonyx. Research labs in Germany, Denmark and Poland are also involved in the scientific effort.