Semiconductor Manufacturing Research News
The search for new memory types has extended to a structure which uses silicon nanodots to store charge, combined with a metallic layer which serves as the metal gate.
According to a team of researchers from Taiwan and the University of California, Berkeley, the 3nm-diameter nanodots can be written and erased much more quickly than today’s charge-storage memories, with a program/erase speed of 1 μs under operating voltages of ± 7 V.
The approach uses ultra-short bursts of green laser light to selectively anneal and activate regions around the metal layer. The sub-millisecond laser pulses are able to create gates over specific clusters of nanodots, without influencing other regions, according to a report in Applied Physics Letters.
“The metal-gate structure is a mainstream technology on the path toward nanoscale complementary metal-oxide-semiconductor (CMOS) memory technology,” said co-author Jia-Min Shieh, a researcher at the National Nano Device Laboratories (Hsinchu, Taiwan). The materials are compatible with a CMOS fab, he added.
Heat Transfer Unraveled
Through atomic-scale manipulation, Illinois researchers have demonstrated that a single layer of atoms can disrupt or enhance heat flow across an interface. Credit: Mark Losego
Researchers at the University of Illinois have revealed new insights about how heat flows across an interface between two materials, improving what is now an incomplete understanding of how heat is conducted.
Using a combination of atomic-scale materials design and ultrafast measurements, the researchers showed that a single layer of atoms can disrupt or enhance heat flow across an interface.
Integrated circuits, combustion engines, and emerging technologies such as thermoelectric devices — which harvest renewable energy from waste heat – require an improved understanding of heat exchange.
“Heat travels through electrically insulating materials via ‘phonons,’ which are collective vibrations of atoms that travel like waves through a material,” said Illinois professor David Cahill, a co-author of the paper. “Compared to our knowledge of how electricity and light travel through materials, scientists’ knowledge of heat flow is rather rudimentary,” he said in a report issued by the university. Their results are published this week in Nature Materials.
Cahill’s group developed a measurement technique using very short laser pulses, lasting only one trillionth of a second, to probe heat flow accurately with nanometer-depth resolution. Changing even a single layer of atoms at the interface between two materials significantly impacts heat flow across the interface, according to Mark Losego, a lead researcher in the effort.
– By David Lammers
Tags: Berkeley, heat transfer, Illinois, Nanodots, non-volatile memory