By Jeff Dorsch, Contributing Editor
The short answer to that headline’s question is “no.” Longer term, in going beyond the 5-nanometer process node, silicon may finally reach the end of its usefulness to the semiconductor industry.
SEMI estimates the worldwide semiconductor materials market grew 3 percent in 2014 to $44.3 billion, compared with 2013’s $43.05 billion. The 2014 total was composed of $24.0 billion in wafer fabrication materials and $20.4 billion in packaging materials. Taiwan last year remained the world’s largest consumer of semiconductor materials, accounting for $9.58 billion in sales, an 8 percent increase from the prior year’s $8.91 billion.
SEMI’s Silicon Manufacturers Group reports silicon wafer area shipments increased 11 percent in 2014 to 10,098 million square inches, as against 9,067 MSI in 2013. Revenues, however, grew only 1 percent year-to-year, to $7.6 billion from $7.5 billion, still far below the 2007 peak of $12.1 billion.
Researchers around the world are constantly investigating materials that could be the successor to silicon. Molybdenum disulfide shows promise. Graphene, the “wonder material” with many exciting attributes, is difficult to employ as a semiconductor material due to its lack of a bandgap, although bandgaps can be found in bilayer graphene or graphene nanoribbons.
Closer at hand are silicon carbide and the III-V materials, such as gallium arsenide and gallium nitride.
Scott Balaguer, Edwards’ president of the U.S. & Europe Semiconductor Business Unit, observes, “Chemistries, gas flows and materials are constantly changing across numerous applications and design nodes. We see these innovations in both silicon and compound semiconductor technologies. A great example is the new prototype SiC line at SUNY Polytechnic Institute that General Electric is driving in Albany, New York.
“The rate and pace of 10nm development is picking up and 14nm HVM fabs continue to improve and efficiencies and achieve higher yields.
“Clearly the rate of EUV adoption has gained momentum as source performance and throughput has improved. It is not a question of if, it is just when,” Balaguer says.
Thomas Piliszczuk, senior vice president of marketing, business development, and global sales for Soitec, says radio-frequency silicon-on-insulator technology is becoming mainstream and has seen “huge growth over the past several years.” He adds, “SOI is today in 99 percent of smartphones.”
On the fully-depleted silicon-on-insulator front, the industry today is at a tipping point with strong industry support and a growing ecosystem. The low-power, significant performance, and cost benefit attributes of FD-SOI are making the technology attractive for mobile, wearable devices, and the Internet of Things, as well as automotive and networking applications, according to Piliszczuk. “FD-SOI is a cheaper solution, overall,” he says. The executive looks for it to soon become “a very high-volume market.”
“The ecosystem now sees SOI not as a niche any more, but as a robust technology for many consumer applications,” Piliszczuk concludes. Shin-Etsu Handotai and SunEdison Semiconductor have joined Soitec as SOI wafer suppliers.
EUV and immersion lithography are expected to usher in the 7nm and 5nm process nodes. What happens past N7 and N5?
An Steegen, senior vice president of process technology for imec, looks ahead to nanowires and high-mobility channels in semiconductors of the future. Those nanowires will be made of silicon or silicon germanium, she says, with germanium in the channel.
That technology will have its drawbacks, she acknowledges. “One nanowire will never beat the performance of one FinFET,” Steegen says.
IBM Research has touted the future use of carbon nanotubes in transistors.
So, don’t write off silicon for now. The old reliable material may have years of usefulness ahead, whether in compound semiconductors or on its own.