‘3D’ transistors promise faster circuits and lighter laptops

A new type of transistor based on a 3D structure could replace silicon chips, say researchers from Purdue and Harvard universities.

The transistors contain tiny nanowires made from called indium-gallium-arsenide. Using them, integrated circuits could be made faster, more compact and more efficient, and laptops lighter, says the team.

And because the device was created using a ‘top-down’ method similar to current industrial processes, it has a good chance of being adopted by industry, they say.

A new generation of silicon computer chips is due to appear next year, using transistors with a vertical structure instead of a conventional flat design. However, because silicon has a limited electron mobility, their performance will be similarly limited.

Indium-gallium-arsenide is among several promising replacements for silicon. They’re called III-V materials because they combine elements from the third and fifth groups of the periodic table.

“Industry and academia are racing to develop transistors from the III-V materials,” says Peide Ye, a professor of electrical and computer engineering at Purdue.

“Here, we have made the world’s first 3-D gate-all-around transistor on much higher-mobility material than silicon, the indium-gallium-arsenide.”

The device has the potential to conduct electrons five times faster than silicon, says the team.

The device could also have implications for power consumption. The team used a new type of insulating layer – essential for the devices to switch off. They applied a dielectric coating made of aluminum oxide using atomic layer deposition, already commonly used in industry.

Using atomic layer deposition might enable engineers to design transistors having thinner oxide and metal layers for the gates, possibly consuming far less electricity than silicon devices.

“A thinner dielectric layer means speed goes up and voltage requirements go down,” Ye said.