Metal oxide, known to start and stop current, can also create it; a step “beyond CMOS”.
Scientists have taken a common component of digital devices and endowed it with a previously unobserved capability, opening the door to a new generation of silicon-based electronic devices.
While digital circuits in computers and cell phones are becoming smaller and processors are going faster and faster, limits are approaching, and scientists worldwide are working to extend or go beyond today’s technology, known as complementary metal oxide semiconductor or CMOS technology
In a research article published in July 2019 in Physical Review Letters, the scientists explain how they created a metal oxide – the “MO” in “CMOS” – equipped with an additional important function. Instead of simply being a passive element of the on-off switch in a CMOS transistor, the new metal oxide activates electrical current flow all by itself. The finding could one day help move computing into an era often called “beyond CMOS.”
The oxide material creates current in nearby pure, “undoped” silicon, the workhorse semiconductor of the electronics industry. The conductivity in silicon takes place in a very thin region just nine atomic layers thick. You’d need to stack 100,000 such layers equal to the width of a human hair.
This capability – to induce current in silicon – marks a major step forward for a material that has previously been thought of as being of limited value; it has performed the on-off duties of an insulator very well but it hasn’t been considered for the crucial current-creating capacity on which all transistors rely.
“The fact that an oxide, long used only as a passive element in semiconductor devices, can also be an active element is new and intriguing,” said Scott Chambers, one of the authors and a scientist at the Department of Energy’s Pacific Northwest National Laboratory.