Coherent Secures $1 Billion Investment in Silicon Carbide Power Substrates for Electric Vehicles

Coherent of Saxonburg, PA announced on April 8 that Japanese auto suppliers DENSO and Mitsubishi Electric have invested $1 billion into its silicon carbide business, holding a 12.5% non-controlling stake in a newly established subsidiary that will operate the business under Sohail Khan, Executive VP of New Ventures and Wide Bandgap Electronics Technology at Coherent.

What is SiC?

As demand for electric vehicles rises, manufacturers are investing more heavily in silicon carbide (SiC) power semiconductor chips to lower costs and increase efficiency. SiC devices have proven more cost-effective energy conversion efficiencies than silicon ones (Si).

SiC semiconductors can switch at higher frequencies, increasing speed and efficiency while decreasing power loss compared to conventional Si. Additionally, their lower heat emissions enable more energy to be absorbed by motors which extend battery range.

While SiC power semiconductors boast numerous advantages, their wider adoption remains limited by cost and wafer availability issues. To address these concerns, Coherent, a Pennsylvania-based maker of lasers and switches for circuits, has launched a subsidiary dedicated solely to SiC production; Coherent hopes this move will result in increased revenues by approximately one billion in 2022.

Coherent executive VP Sohail Khan will manage this new subsidiary, and has already secured long-term supply agreements with two Japanese EV providers DENSO Corp of Kariya Aichi Prefecture and Mitsubishi Electric Corp of Tokyo that grant each firm an equity stake worth $500 million in total for one billion total investment in their subsidiary.

DENSO will use silicon carbide substrates from Mitsubishi Electric to construct inverters used in electric vehicle (EV) power systems that drive and control motors, while DENSO will use them to fabricate SiC modules used to convert electric current into usable energy.

In order to produce high-quality substrates, the subsidiary uses a continuous epitaxial growth process to form a continuous layer of SiC c-plane material and then applies chemical vapor deposition (CVD). Finally, substrates are cut off and processed into individual semiconductor chips for manufacturing purposes.

Khan anticipates that 200 mm diameter substrates will become the dominant size by 2025, when an assembly line for their production will have been opened and all required tools approved for qualification.

Anvendelser

As global adoption of electric vehicles (EVs) surges, semiconductor demand for silicon carbide has seen exponential growth. This material provides advantages over traditional silicon for high-temperature and high-frequency applications such as power converters. Coherent’s former II-VI business has long provided 150mm and 200mm substrates, as well as epitaxial wafers to serve this market.

SiC is ideal for use in harsh environments due to its superior thermal conductivity, making it suitable for applications that include automotive, telecoms, aerospace and marine power systems as well as industrial power converters. SiC’s ability to withstand higher temperatures and challenging environmental conditions found within these devices results in lower overall system cost, weight, size and complexity; additionally it reduces cooling requirements and allows smaller-footprint packages that improve power density.

SiC’s low nuclear spin density also allows it to support longer electron spin decoherence times than diamond, as demonstrated in a recent study with single electron spin qubits utilizing SiC ground state spins with an expected T1 time of 100 us compared with 50 us for diamond qubits.

Studies using Cr defects with 3d2 electronic configuration created non-degenerate orbital triplet ground states and non-degenerate 1E spin singlet orbital doublet excited states that are spin forbidden for transition between them; creating low energy gaps with long decay times suitable for quantum communication applications.

Cr4+ can be produced in deep SiC using high-energy ion implantation, followed by 1800 degC annealing to stabilize and minimize optically active background noise. Off-resonant photoluminescence at 30 K clearly displays detection of Cr4+ signals with high spatial resolution and strong decoupling properties.

This transaction also enables DENSO and Mitsubishi Electric to secure reliable supplies of quality 200mm wafers from Coherent’s Saxonburg facility, supporting their demand for 150mm and 200mm substrates necessary to produce power semiconductor devices that extend BEV range beyond what would be possible with traditional silicon chips.

Processes

Coherent has expanded its Palmer Township facility in Pennsylvania in order to keep pace with increasing demand for silicon carbide chips, producing lasers and switches used in electronic circuits as well as offering silicon carbide wafers that increase electric vehicle range more effectively than silicon based wafers.

US company has secured a $1 billion investment from two Japanese firms that supply products using SiC power devices, along with concurrent supply agreements that will speed up capital plans for business growth.

DENSO and Mitsubishi Electric each will own 12.5% of shares in Silicon Carbide, the newly established subsidiary. Both firms have long-term supply agreements with this subsidiary. Both manufacturers manufacture electronic devices including SiC power devices such as inverters for electric vehicles – ranking among the world’s top producers of such devices.

Silicon carbide offers higher temperature resistance and chemical stability than its alternative, traditional silicon, while being more eco-friendly material. Companies supplying silicon-carbide substrates require long-term reliability for customer applications. Silicon carbide provides this material.

Researchers from Argonne National Laboratory have developed an advanced manufacturing process that produces high-grade silicon carbide wafers using an atomic-vapor deposition (APVD) technique to deposit silicon carbide layers on glass substrates – producing wafers with purity levels surpassing current industry standards.

Scientists also advanced a SiC-based quantum sensor by employing a new technique for detecting spin decay from a single qubit and increasing coherence time of the device. Their method combined microwave pulses with all-electrical readout of its magnetic resonance, improving signal-to-noise ratio measurements for spin decay measurements as well as measuring properties like Rabi spin nutation and dephasing.

This new technology promises high-throughput, high-resolution imaging of chemical and biological samples in the laboratory, leading to more precise diagnoses of diseases in plants, animals and humans. Scientists expect it will also be useful for drug discovery as well as screening drinking water and foodstuffs for contaminants.

Prisfastsættelse

Cost has long been a significant impediment to electric vehicle manufacturing, yet that may soon change with new investments and planned commercial shipments of high-quality yet economical substrates.

On Tuesday, Coherent announced that Japanese firms Denso and Mitsubishi Electric had invested $1 billion into its silicon carbide business located in Saxonburg, Pennsylvania. Each firm now holds 12.5% ownership in this $4 billion unit while Coherent retains 75% and operates it independently as an independent subsidiary; additionally, this deal also includes long-term supply agreements.

Silicon carbide semiconductors, lasers and switches are among the many products manufactured at this unit. Their customers include manufacturers of telecommunications networks, medical devices, aerospace/defense systems, energy companies, semiconductor device makers and research labs. While demand has decreased recently, the company anticipates growth will resume by 2024.

Coherent’s revenue has been under threat from soft sales across industrial, instrumental, and consumer electronics markets; post-pandemic communications market slowdown; and slow recovery in China. Over the past year its stock price has declined by 22% versus 10% gain on S&P 500 Electronic Components Index.

Numerous companies are developing silicon carbide (SiC) power electronics chips. These are essential to producing electric vehicles as they expand the range. Unfortunately, manufacturing these complex and costly chips is expensive and complex. Thus, many SiC producers have taken significant steps to increase production capacities; Germany’s Wolfspeed was particularly notable.

Firm has announced it will increase production of GaN-on-SiC RF power amplifiers and other microwave devices with high-quality semi-insulating SiC substrates, marking an important step toward mass production of SiC power electronics. Available substrate sizes range between 150 mm and 200 mm diameters with the latter size expected to become dominant by 2025; processing lines have already been set up while tools undergo qualification processes for processing these larger substrates.