TOKYO/OSAKA -- Abundant, easily processed silicon has been the material of choice for decades in the semiconductor industry, but electric vehicles are helping chip away at its dominance in the pursuit of energy efficiency.
Tesla has been a catalyst for this change. The U.S. automaker became the first of its peers to use silicon carbide chips in a mass-produced car, incorporating them into some of its Model 3s. This move gave the power-saving material a boost of momentum in the EV supply chain, with ramifications for the chip industry.
"Thus far, chipmakers have worked together to build up the silicon carbide market, but we've reached the stage of competing with each other," said Kazuhide Ino, chief strategy officer at Japanese chipmaker Rohm.
Silicon carbide, abbreviated SiC, contains silicon and carbon. With chemical bonds stronger than those in silicon, it is the world's third-hardest substance. Processing it requires advanced technology, but the material's stability and other properties let chipmakers cut energy loss by more than half compared with standard silicon wafers.
SiC chips also dissipate heat well, allowing for smaller inverters -- a crucial EV component that regulates the flow of power to the motor.
"The Model 3 has an air resistance factor as low as a sports car's," said Masayoshi Yamamoto, a professor at Nagoya University in Japan. "Scaling down inverters enabled its streamlined design."
A Tesla Model 3 inverter containing silicon carbide chips is seen during a teardown. (Photo courtesy of Nagoya University professor Masayoshi Yamamoto)
Tesla's move jolted the chip industry. In June, German chipmaker Infineon Technologies introduced an SiC module for electric vehicle inverters.
"The timing of the expansion of SiC has clearly moved closer than what we had expected," said Takemi Kouzu, manager at Infineon's Japan unit.
Hyundai Motor will use Infineon-made SiC chips in its next-generation EV. These chips are said to enable a more than 5% increase in vehicle range compared with silicon.
French automaker Renault signed a deal in June with Switzerland-based STMicroelectronics for a supply of SiC chips beginning in 2026. The agreement also covers chips made with gallium nitride, another alternative material for semiconductor wafers.
The market for SiC power chips will grow sixfold by 2026 compared with 2020, reaching $4.48 billion, French market research firm Yole Developpement forecasts.
The price gap between silicon and more costly SiC is narrowing. Mass production and other factors have shrunk the difference in cost to about double, from roughly tenfold as recently as five years ago, Yamamoto said. With some chip industry suppliers starting to make bigger SiC wafers, this gap could narrow even further.
Rohm has been a leader in the field, mass-producing the world's first SiC transistor in 2010. German unit SiCrystal, acquired in 2009, makes SiC wafers, giving Rohm a start-to-finish production capability. The Japanese company aims to reach a 30% global market share in SiC chips by fiscal 2025. It recently opened a additional production facility at a plant in Japan's Fukuoka Prefecture, part of plans to grow capacity more than fivefold.
Rohm said a number of upcoming electric vehicle models will use its SiC chips. It also has an agreement with Chinese EV maker Geely on technology for next-generation chips.
Silicon was not the first chip material. After the groundbreaking invention of the transistor at Bell Laboratories in the U.S. in 1947, germanium crystals were used. Silicon replaced this element in the 1960s as the semiconductor industry took off. Two of the world's biggest silicon wafer suppliers -- Shin-Etsu Chemical and Sumco -- are based in Japan.
SiC also has rivals as an alternative to silicon. Gallium nitride (GaN) holds the potential to cut energy loss to about one-tenth as much as with silicon chips. The use of this material in semiconductors was developed in Japan to create blue light-emitting diodes. While GaN chips are used in some areas, such as charging devices, the material has yet to show its full potential because it has mostly been used in conjunction with other materials, including silicon.
The search for alternatives to silicon reflects the increasingly apparent limits to improvement in chip performance. The development of smaller, more powerful electronics requires etching ever more minute circuit patterns. With this scale now at 5 nanometers (1 nanometer equals one billionth of a meter), the projection that transistor density will double roughly every two years -- known as Moore's Law -- is being tested like never before.
Energy conservation also drives innovations in chip materials. The expansion of EVs, data centers and other building blocks of the digital economy will create vast unmet demand for electricity without steps to improve energy efficiency.
U.S. startup Lab 91, a spinoff of the University of Texas at Austin, is developing technology to overlay graphene -- sheets of carbon just one atom thick -- on chip wafers. Early trials have been successful, and the company is in talks with chipmakers on evaluating the technology for mass production. Graphene holds the potential to improve chip performance in a wide range of applications, from EVs to LEDs to image sensors used in smartphone cameras.
Diamond -- called by some the ultimate semiconductor -- is a potentially game-changing but costly alternative to silicon. Tokyo-based manufacturer Adamant Namiki Precision Jewel has developed technology for producing power chips with diamond. The world's hardest substance has a theoretical ability to cut energy loss to one-50,000th as much as silicon. But making such chips cost-effective will be key. Diamond substrates now cost thousands of times as much as silicon wafers.
With semiconductors vital to national security and economic competitiveness, governments in China, the U.S. and Europe are looking to back research and development into new chip materials. Support for R&D and investment in this field was part of a semiconductor strategy issued by Japan's Ministry of Economy, Trade and Industry in June. As silicon stood alongside steel as one of the materials that built the 20th century, the next great semiconductor material looks likely to become a driver of international competition in the coming decades.
