Coherent Closes $1 Billion Investment in Silicon Carbide Substrates

Coherent has announced that Japan-based DENSO and Mitsubishi Electric will jointly invest $1 billion into its SiC substrate business, creating a subsidiary offering 150 mm and 200 mm SiC substrates as well as epitaxial wafers.

SiC is an attractive material for power semiconductors as it can reduce power loss while operating at higher temperatures than silicon. Furthermore, SiC’s small form factor and lower weight reduce device size and weight significantly.

High-temperature

Silicon carbide (SiC) is an invaluable material for electronics that operate at high temperatures or voltages, as its high thermal conductivity and electrical conduction resistance enable power semiconductor devices with SiC components to significantly decrease energy loss and switch-on time when compared with silicon-based technology. Furthermore, it can operate at higher switching frequencies than silicon due to lower electrical conduction resistance; moreover its very strong construction means higher switching frequencies can be reached than with silicon technology alone. Unfortunately its low density and cost have prevented widespread commercialization; though some small mined natural sources such as moissanite jewels but most SiC used in electronic devices is produced synthetically by electronics manufacturing facilities rather than natural sources like moissanite jewels mined naturally from moissanite jewels mined from natural sources; most electronic device makers produces silicon carbide using synthetic precursors instead.

Researchers have studied the optical and magnetic properties of vacancy-related spin defects in SiC in order to address these challenges, uncovering that certain can be coherently controlled even at room temperature; this represents a major milestone, since other known defect systems in SiC have extremely short coherence times; this work opens up a whole host of applications for spin defects in SiC, such as quantum information tasks.

Researchers investigated the optical and magneto-optical properties of PL8 defects generated through hydrogen ion implantation with subsequent post-annealing at high temperatures. Fluorescence and optically detected magnetic resonance (ODMR) signals were observed at both low and high temperatures; at lower temperatures ODMR signals for these defects displayed a Lorentz fit with fifth order polynomial temperature dependence while higher temperature signals displayed a clear cut-off with zero-field scattering strength.

Researchers then employed Ramsey pulse sequences to accurately measure the free induction decay time (T2ast) of these PL8 defect spins, showing their free induction decay is power dependent – an essential characteristic for coherent spin systems.

This research is published in Nature Nanotechnology and made possible thanks to an investment of $1 billion by Japanese firms DENSO and Mitsubishi Electric into Coherent’s SiC business, for which they will receive 12.5% non-controlling ownership stake as well as long-term supply agreements to meet demand for 150mm and 200mm substrates and epitaxial wafers; closing date expected early 2024.

High-frequency

Silicon carbide (SiC) is an extraordinary semiconductor material with remarkable thermal, optical, and mechanical properties that makes it suitable for use in high-power electronics, micromechanical sensors, astronomical telescopes and many other applications. SiC devices tend to offer lower switching losses than silicon (SI) chips while operating at higher temperatures for reduced power loss and increased efficiency.

Silicon carbide not only boasts exceptional temperature resistance but it is also highly conductive; more than 10 times as conductive as pure silicon. Due to this property, silicon carbide’s ability to conduct current at high speeds allows it to achieve low switching losses and fast operation for improved efficiency and reduced energy costs. Furthermore, silicon carbide’s ability to tolerate high voltages without damaging devices makes it suitable for high-speed applications like motors and drives.

SiC was previously limited in high-frequency applications due to its high switching losses and heat generation, however this problem was recently solved using a doping technique using nitrides-based dopants that reduced these switching losses and enhanced its performance at high frequencies. By employing this approach it became possible to manufacture high-speed transistors and high-voltage diodes with greater breakdown voltages and faster operations than existing technologies.

Nitrides-based doping involves mixing silicon with nitrogen in manufacturing to form carbon vacancies that give silicon carbide its exceptional frequency-quality characteristics, enabling it to handle large electric currents at high frequencies – ideal for motors and drives as well as telecom and radar systems.

Researchers have investigated the properties and defect structures of silicon carbide, but little is known about its spin behavior at high temperature. After studying their spin behavior at this temperature level, researchers have discovered that zero-field splitting of SiC defect spins depends on temperature; their spin coherence decreases with increasing temperature – an observation which could pave the way for new high temperature spin electronics applications.

Coherent Corp of Saxonburg, Pennsylvania recently secured a $1 billion investment from two Japanese electric-vehicle market providers DENSO Corp and Mitsubishi Electric Corporation from Kariya in Aichi prefecture. Both investors hold 12.5% stakes in Coherent’s newly formed subsidiary and long-term supply agreements which will aid its growth.

High-voltage

Silicon Carbide (SiC) is an extremely robust chemical compound composed of silicon and carbon atoms bonded together via covalent bonds, similar to those seen in diamonds, with strong covalent interactions similar to diamonds. SiC features hexagonal crystal structure and wide band gap semiconductor properties. Furthermore, SiC’s band gap energy is nearly three times greater than silicon’s, meaning that electricity can flow without incurring much loss during transmission; making SiC ideal for high voltage applications like electric vehicle power sources.

SiC is also much more durable than other semiconductors, enabling components to withstand higher temperatures without needing cooling systems to keep operating efficiently. This enables electric vehicles to achieve better fuel efficiency and driving range. Furthermore, using SiC-made semiconductor chips means power electronics in these vehicles are equipped with power electronics capable of withstanding higher switching frequencies and temperatures than those made entirely out of silicon (Si).

Coherent, which offers laser equipment and semiconductor wafers, has already witnessed an upsurge in demand for its SiC products. Their sales increased by 50 percent in the first quarter of 2024 thanks to new orders from companies planning high-performance electric vehicles (EV).

This investment will enable the company to expand its production capacity while improving manufacturing processes and developing new technologies. Alongside producing SiC wafers, the company plans on making GaN-on-SiC RF power amplifiers as well as other RF and microwave devices – not forgetting resonator cavities which will amplify output power for these devices.

Denso and Mitsubishi Electric’s investment is expected to bring the value of Coherent’s SiC business beyond $1 billion. Each Japanese firm will gain non-controlling 12.5 percent stakes in Coherent’s new subsidiary run by Sohail Khan, executive VP for wide bandgap electronics technology at Coherent. In addition, long-term supply agreements will be signed between these parties with this subsidiary before its closure by 2024 first quarter.

Lightweight

Coherent, an US maker of high-tech equipment, announced today it has received an investment of $1 billion from two Japanese electric car suppliers to establish its silicon carbide (SiC) semiconductor business. Denso Corp and Mitsubishi Electric both invested $500 million each as per an announcement by Coherent on 10 October; as an exchange for their stakes they have entered long-term supply agreements with Coherent.

SiC, short for silicon carbon, is a hard chemical compound with the crystal structure resembling that of diamond. While naturally found as moissanite mineral, mass production since 1893 has seen SiC produced as powder or crystal form and used in hard ceramic applications like automobile brakes, clutches and bulletproof vest plates. Large single crystals may also be grown and cut into gems known as synthetic moissanite gems or ground into industrial materials like alumina and tungsten carbide for manufacturing uses.

Coherent’s SiC business has an established track record in providing wafers for power electronics devices. SiC’s market-leading thermal conductivity enables power modules to dissipate heat more effectively, helping reduce power loss and increase performance while its superior electrical properties give an edge over silicon.

Silicon carbide stands out for its thermal properties as well as its low coefficient of expansion, making it suitable for use in high voltage applications. Furthermore, its durability is impressive with an exceptional strength-to-weight ratio and easy machining features making it attractive for use in precision tools.

The new subsidiary will engage customers at every step of their devices’ creation, from manufacturing SiC substrates and epitaxial wafers to designing components that make up finished devices and modules. Khan says his company’s goal is to understand its customers and create solutions tailored specifically to meet their needs, and believes the new subsidiary can capture a substantial share of this growing market.