New Memory Chip Uses Stacked Cells

In a 1965 scientific paper, Intel Co-founder Gordon E. Moore wrote that the number of transistors that could inexpensively be placed on a computer chip would double about once every two years. Until now, this prediction – which came to be known as Moore's Law – has held true, but the technology employed by the industry is currently beginning to reach its limit. Recently, Arizona State University (ASU) experts announced that they might have found a way to make the law sustainable for longer.

Their new device is based on a very elegant construction, which was done entirely using available materials. The instrument essentially isolates individual cells inside memory chips, allowing the Law's unavoidable effects to be stalled for longer than originally thought. The new chips developed by the ASU team are based on the “ionic memory technology,” which is a type of stackable memory. The method, which uses regular electronic materials, could help store more data in high-density computer memories.

The work was led by the Director of the ASU Center for Applied Nanoionics, Michael Kozicki. He is also a professor of electrical engineering at the university. “This opens the door to inexpensive, high-density data storage by 'stacking' memory layers on top one another inside a single chip. This could lead to hard drive data storage capacity on a chip, which enables portable systems that are smaller, more rugged and able to go longer between battery charges,” the expert says.

“This is a significant improvement on the technology we developed two years ago where we made a new type of memory that could replace Flash, using materials common to the semiconductor industry (copper-doped silicon dioxide). What we have done now is add some critical functionality to the memory cell merely by involving another common material – silicon,” he adds. Details of the work were presented this November at the 2009 International Electron Devices and Materials Symposia, held in Taiwan. The expert collaborated with ASU electrical engineering graduate student Sarath C. Puthen Thermadam for the work.

“Before, if you joined several memory cells together you wouldn't be able to access one without accessing all of the others because they were all wired together. What we did was put in an access, or isolation device, that electrically splits all of them into individual cells,” Kozicki concludes.