Transparent Silicon Carbide: Wolfspeed Bets on AR

Wolfspeed has started selling transparent silicon carbide, aiming a material best known for electric-car power chips at the makers of augmented reality (AR) glasses and quantum computers. The Durham, North Carolina company announced the commercial launch on 29 October under the brand TSiC, and has posted a specification sheet with part numbers for the wafers.

The launch puts a clear crystal, rather than a finished device, into the market. Wolfspeed names no customers and gives no prices or volumes, and the performance claims come from the company itself or from an outside expert it quoted in the release.

In brief

Wolfspeed has launched transparent silicon carbide wafers, branded TSiC, for AR glasses, quantum computing and other optical uses.
Its spec sheet lists 150 mm and 200 mm part numbers, an absorption ceiling and flatness figures, and offers samples on request.
No customers, prices or volumes are disclosed, and the two Wolfspeed sources describe 300 mm wafers differently.

What Wolfspeed says transparent silicon carbide can do

Wolfspeed describes its optical-grade substrates as “engineered for exceptionally low optical absorption and superior wafer flatness”. In plain terms, the wafers are meant to let visible light through with very little loss and to be extremely even across their surface.

The AR case for transparent silicon carbide rests on the properties of the crystal itself. The release says its “high refractive index, low birefringence, hardness and thermal conductivity” make it “a promising material for next-generation AR waveguides, supporting wider fields of view, improved image quality and more compact wearable devices”. A waveguide is the thin transparent layer in AR glasses that carries a projected image across the lens to the wearer’s eye.

Wolfspeed’s product page adds a weight argument: the thermal properties of its transparent silicon carbide “enable a reduction in embedded heat sinks, significantly reducing the weight of AR glasses”. It also cites hardness, saying lenses made from it will endure daily wear and tear.

The strongest words come from Barry Silverstein, an optics expert at the University of Rochester who was previously chief technology officer and senior director of optics and display products at Meta Reality Labs. “Its exceptionally high refractive index lets a single-layer waveguide do the work that previously took stacked optics,” he said in the release, calling that the kind of step-change needed “to move AR from a novelty into everyday eyewear”.

On quantum computing, the release says the material can host quantum bits (qubits), preserve their quantum states and “transmit quantum information through light—all within a single silicon carbide crystal”. The product page is more measured, saying the material’s properties “are being explored” as a cryogenic packaging substrate, a low-loss photonic platform and a host for engineered spin-defect qubits.

The spec sheet lists 150 mm and 200 mm optical-grade substrates

The product page is where the launch becomes concrete. It says Wolfspeed was granted a US patent in July 2024 for “reduced optical absorption techniques”, and lists two part numbers: W4WPG0S-N-0200 for 150 mm wafers and W4WPH0S-N-0200 for 200 mm.

The target specifications are a thickness of 500 µm, plus or minus 20 µm; an absorption coefficient of no more than 0.05 cm-1 across 450 to 650 nanometres, roughly the visible range from blue to red; total thickness variation of no more than 1.5 µm; and optical roughness of no more than 1 nm on both polished sides. The wafers are 4H silicon carbide, the crystal type Wolfspeed already sells. The page notes that specifications may vary by diameter and invites buyers to request samples.

The two primaries describe the largest size differently. The release says Wolfspeed “continues advancing its 200 mm optical-grade substrates while developing 300 mm TSiC™ technology”. The product page says 300 mm is “sampling” and lists it as available “on request”.

Katrin Feurle, vice president of Wolfspeed’s Beyond Power unit, said the technology and the company’s patents “position us to help enable breakthroughs in augmented reality, quantum computing and other emerging markets”. The release ties TSiC to more than 35 years of silicon carbide work at Wolfspeed, including LEDs and high-purity semi-insulating wafers.

The launch follows two power-chip announcements this month: an expanded 200 mm wafer supply deal with Infineon on 15 October and a multiyear silicon carbide device agreement for electric vehicles on 28 October.

Wolfspeed’s AR case rests on its own numbers and one expert

The launch is a materials offer, and it should be read as one. Wolfspeed has published enough detail on its transparent silicon carbide for an optics engineer to test the wafers against rivals: part numbers, an absorption ceiling, flatness and roughness figures, and a sample request route. That is more than many launch releases give. What it has not published is any sign that a glasses maker or quantum lab has chosen TSiC, at what price, or in what quantity, so the commercial case is still a claim.

The AR argument also leans on a single outside voice. Silverstein’s Meta background gives his view weight, but he speaks about silicon carbide as a material, not about results from a specific Wolfspeed wafer in a product. Glasses such as XREAL’s Android XR headset show the form factor is shipping now, yet nothing in either primary links TSiC to any of them.

The quantum section is the most hedged once both sources are read together. The release lists what silicon carbide can do; the product page says those uses are “being explored”. Companies such as PsiQuantum, which builds quantum hardware from light, are the kind of buyer the photonic claim is aimed at, but Wolfspeed names none. The gap between “developing” and “sampling” for 300 mm wafers is small, but it is one the two Wolfspeed sources leave unreconciled.

Wolfspeed’s next scheduled public update is its fiscal first-quarter earnings call on 4 November.