Coherent Silicon Carbide Boosts Electric Vehicle Range

Coherent has attracted the interest of four Japanese conglomerates for an investment in its silicon carbide business, which manufactures chips that extend EV range more effectively than those made using traditional semiconductor silicon technology. At present, Coherent holds over $4.3 billion of debt.

The chromium defect in SiC hosts electron spins with long coherence times that could enable hybrid solid-state qubits. There are quantitative measurement techniques such as Glow Discharge Mass Spectrometry and X-Ray Fluorescence spectroscopy available for solid samples to make measurements.

What is Silicon Carbide?

Silicon carbide (or silicon nitride) is an extremely hard, synthetic crystalline compound of silicon and carbon, developed first in the late 19th century and widely used since. Applications include abrasives, grinding wheels, cutting tools, wear-resistant parts of pumps and rocket engines as well as semiconducting substrates for light emitting diodes (LED). Furthermore, due to its low thermal expansion rates and superior mechanical properties this material makes an excellent mirror material in astronomical telescopes.

Coherent silicon carbide (commonly referred to as CARBOREX) comes in various chemistries and sizes to meet an extensive array of applications and industries. Common uses for CARBOREX may include but are not limited to:

Manufacturing silicon carbide is relatively straightforward: an electric resistance furnace heats a mixture of silica sand and carbon (such as coal) up to 2500 degrees Celsius before stirring chemical reactions take place and produce black or green silicon carbide with layers containing graphite on the inside, alpha-SiC (with coarse crystal structure), beta-SiC metallurgical grade and unreacted raw material on the outside, alpha-SiC being the highest grade with coarse crystal structure, beta-SiC (metallurgical grade), alpha-SiC (the highest grade with coarse crystal structure), beta-SiC (metallurgical grade), alpha-SiC (the highest grade with coarse crystal structure), beta-SiC (metallurgical grade), alpha-SiC grade alphaSiC), beta-SiC (metallurgical grade), alphaSiC (alphaSiC), with coarse crystal structure), alphaSiC being produced outside, beta-SiC (metallurgical grade), alphaSiC (alpha grade with coarse crystal structure), beta-SiC (metallurgical grade), alphaSiC (alpha grade with finer crystal structure), beta-SiC (metallurgical grade), alphaSiC being produced outside), alpha-SiC being produced and unreacted raw material being unreacted raw material being produced outside).

Washington Mills produces finished silicon carbide grades using crushed and sized crude silicon carbide that has been crushed to make finished grades of grains and powders suitable for various applications. Washington Mills supplies various sizes and chemistries of CARBOREX silicon carbide powder to a diverse industry base in powder or grain form, which are then sold for use as abrasives, coated abrasives, refractories grinding wheels insulation metallurgical wiresawing applications or as support material for heterogeneous catalysts among others.

Applications

Power electronics is where silicon carbide (SiC) chips really shine; these powerful transistors can withstand higher voltages without experiencing unpredictable conduction behavior or catastrophic failure, which allows more power to be transferred through each chip and leads to smaller, more compact power electronic systems that save energy, weight and cost while saving energy at the same time.

Technology used in semiconductor metrology can improve measurement accuracy and speed by replacing traditional bulk techniques with more sensitive techniques that offer higher measurement precision and speed, such as Glow Discharge Mass Spectrometry and X-Ray Fluorescence spectroscopy on solid samples; Inductively Coupled Plasma-Optical Emission Spectrometry and ICP-Mass Spectrometry on digested or leached samples; Laser Ablation-Induced Breakdown Spectroscopy/Scanning Electron Microscopy-Energy Dispersive Spectrosography on thin film samples.

DENSO and Mitsubishi Electric have invested significantly in Coherent’s SiC business, entering arm’s length long-term supply agreements for 150 mm and 200 mm substrates and epiwafers as well as devices and modules from Coherent. Khan intends for his company to act as a merchant player, engaging with companies at all stages of the value chain so he can learn from customers while improving production processes ranging from furnaces through epi-reactors all the way down to final products themselves.

Manufacturing

Silicon carbide is a semiconductor material, meaning that its electrical conductivity varies with temperature or pressure. Due to its much wider bandgap compared with that of traditional silicon semiconductors used in modern electronics, silicon carbide has the capacity to move electrical energy faster (Wolfspeed).

Silicon carbide’s hardness, rigidity and thermal conductivity make it the ideal material for mirrors in astronomical telescopes that must withstand extremely high temperatures. Furthermore, its low thermal expansion rate makes it suitable for space instruments that may experience both extreme temperatures and cold environments.

Carborundum, a synthetic form of silicon carbide, is widely used as an abrasive material in grinding and polishing metal surfaces such as car brakes, ceramic plates in bulletproof vests, glass-like ceramic tiles used on some vehicles and aircrafts and car brake pads. Large single crystals of silicon carbide may even be cut to form gemstones known as moissanite gemstones.

Coherent, a supplier of lasers and switches for electronic circuits, has reportedly received interest from Japanese conglomerates interested in investing in its silicon carbide division at up to $5 billion, according to sources who told Reuters on September 22. Such investment would reduce Coherent’s financial strain while permitting it to increase production of its 8-inch silicon carbide wafers needed in power devices that boost electric vehicle range more than regular silicon chips do.

Pricing

Silicon carbide chips’ higher operating temperatures and frequencies should help them reduce power consumption over time, which would make electric vehicles (EVs) more cost-effective to produce and run. Furthermore, SiC can withstand higher voltages and currents than traditional semiconductors.

Japanese automakers Denso and Mitsubishi Electric recently invested a combined $1 billion into Coherent’s silicon carbide unit to value it at approximately $4 billion, according to sources familiar with the matter. That represents a premium given that Coherent itself has an enterprise value of about $11 billion, and its silicon carbide business only accounts for a single-digit percentage of total sales.

The company is expanding its production of 8-inch substrates for epitaxial wafers and anticipates that this larger wafer size can support applications requiring high power/frequency devices.

Demand for silicon carbide technology continues to surge. Yet while Coherent’s revenue skyrocketed 56% year over year to $5.16 billion after II-VI acquired and renamed original Coherent with new name and ticker, networking materials and laser business revenue declined sequentially throughout fiscal 2023.