Metal-insulator-metal (MIM) diodes might just be the technology that allows electronics achieve the next big leap in processing speed. Research into diode design conducted at the Oregon State University (OSU) has revealed this week cheaper and easier to manufacture MIM diodes that will also eliminate speed restrictions of electronic circuits that have baffled materials researchers since the 1960's.

“Researchers have been trying to do this for decades, until now without success. It’s a basic way to eliminate the current speed limitations of electrons that have to move through materials,” OSU materials chemistry professor, Douglas Keszler said. “This is a fundamental change in the way you could produce electronic products at high speed on a huge scale at very low cost, even less than with conventional methods,” he said.

“For a long time, everyone has wanted something that takes us beyond silicon. This could be a way to simply print electronics on a huge size scale even less expensively than we can now. And when the products begin to emerge the increase in speed of operation could be enormous,” Keszler said.

Traditional silicon-based materials used in electronics work by limiting the flow of electrons using transistors, a process that restricts how quickly electrons can move across a circuit – and therefore how quickly your computer or iPhone can load a program. MIM diodes allow almost instantaneous electron transfer through the insulator surface – a major step in eliminating the 50 year-old speed barrier found in transistor based electronics.

The Breakthrough

While MIM diodes have been around for a while now, the biggest problem has been controlling electron flow to make it even across the entire surface of the diode. The breakthrough was to use a super smooth metal ZrCuAlNi in thin film form as opposed Aluminium (Al) which is comparatively rough. The roughness of the Al electrodes used in previous MIM diode research had resulted in poor consistency in electron flow. Now with the flatter ZrCuAlNi electrodes this flow of electrons can be controlled much more easily. So the diode is constructed with two ZrCuAlNi electrodes with a SiO2 insulator layer in between. A patent has been applied for on this new technology.

“When they first started to develop more sophisticated materials for the display industry, they knew this type of MIM diode was what they needed, but they couldn’t make it work,” Keszler said. “Now we can, and it could probably be used with a range of metals that are inexpensive and easily available, like copper, nickel or aluminum. It’s also much simpler, less costly and easier to fabricate.”

University scientists will initially apply the work to innovations in electronic displays, but they say many applications are possible. High speed computers and electronics that aren't limited by transistors are possibilities.

The Paper Advancing MIM Electronics: Amorphous Metal Electrodes is published in Advanced Materials.