Microchips Could Be Used to Activate Excess Dopants
As microchips continue to shrink, silicon must be doped, or mixed, with higher concentrations of phosphorus to produce the desired current. Technology Briefing
Transcript
As microchips continue to shrink, silicon must be doped, or mixed, with higher concentrations of phosphorus to produce the desired current. Semiconductor manufacturers are now approaching a critical limit in which heating the highly doped materials using traditional methods no longer produces consistently functional semiconductors.
The Taiwan Semiconductor Manufacturing Company (or TSMC) theorized that microwaves could be used to activate the excess dopants, but today’s microwave annealers produce "standing waves" that prevented consistent dopant activation. TSMC partnered with Cornell Professor James Hwang, who modified a microwave oven to selectively control where the standing waves occur.
Such precision allows for the proper activation of the dopants without excessive heating or damage to the silicon crystal. "This discovery could be used to produce semiconductor materials and electronics appearing around the year 2025," said Hwang, who has filed two patents for the prototype.
As Hwang explains, "A few manufacturers are currently producing semiconductor materials that are 3 nanometers. This new microwave approach can potentially enable leading manufacturers such as TSMC and Samsung to scale down to just 2 nanometers." The breakthrough, described recently in Applied Physics Letters, could also change the geometry of transistors used in microchips.
For more than 20 years, transistors have been made to stand up like dorsal fins so that more can be packed on each microchip, but manufacturers have recently begun to experiment with a new architecture in which transistors are stacked horizontally. The excessively doped materials enabled by microwave annealing would be key to the new architecture.
