@International Microwave Symposium: Debate ensues over the longevity of silicon

ANAHEIM, Calif. – A group of academics and top systems engineers looked the part in a panel this week at the International Microwave Symposium, but their discussion took on all the makings of political theater. Designed to address whether silicon can operate at THz frequencies, the panelists quickly took their sides on the issue and the standing-room-only crowd was all too pleased to cheer or heckle under their breath every step of the way.
There was the silicon camp and the alternative technologies camp, which of course has plenty of splinter groups as well.
Gabriel Rebeiz, a professor at the University of California, San Diego, kicked off the panel with a bold statement (at least to those in the audience): “Silicon will eat you for lunch.” Perhaps the least objective moderator in the history of panels at a tech conference, Rebeiz made clear that he still sees a bright future ahead for silicon, albeit with some hesitation.
“You do not really need RF silicon,” he said. “The only reason silicon is not (at THz frequencies) is because there is not any high volume.”
Market forces will dictate whether silicon can deliver at THz frequencies, he told the crowd. Simply put, “if there are market forces, it will do it,” he said.
Hooman Kazemi of HRL Laboratories jumped in to make his case for indium phosphide, an alternative to silicon. The man difference between silicon and phosphate is that silicon requires the gain and noise filter need to be in the same chipset and that increases noise overall, he said.
“If you can do it with silicon I think we should, but I don’t think you can,” he concluded.
Sorin Voinigescu, a professor at the University of Toronto, said higher volumes will have to come in before silicon truly reaches anything beyond 100 GHz. But right now, it’s nothing more than research. The applications that exist today do not require anything beyond what’s currently available, he said.
“We don’t know what to apply it for,” he said. “I don’t think silicon will be at THz anytime in the next 10 years.”
Finally, Mark Rodwell, a professor of electrical and computer engineering at U.C. Santa Barbara, said silicon will continue to scale until physics or economics stops it.
The panel made it abundantly clear that silicon is the path of the status quo. Moreover, there’s little to indicate that the principal component of most semiconductor devices is running short on runway anytime soon.