Soitec Makes AI Wafer Customers Put Up Cash to Lock In Multi-Year Supply

Soitec, the French company that supplies the thin silicon wafers underneath nearly every optical chip used in AI data centers, is asking its customers to put up cash and commit to multi-year volumes, with the deposit forfeited if they fall short. The substrate layer of the AI buildout, long treated as a commodity, is starting to behave like a constrained, pricing-power market.

UBS estimates the company holds roughly 95% of the silicon photonics substrate market, the engineered wafers that let data move between chips using light instead of electricity. With that share, Soitec sits at the chokepoint under the optical interconnects that hyperscalers, the largest cloud and AI operators, are racing to install as they push past the limits of copper cabling inside AI clusters. The company's stock has almost quadrupled this year on that thesis.

The new contract terms are take-or-pay in everything but name. Customers must put down a deposit tied to committed demand, accept fixed pricing, and share inventory data to prevent over-ordering and capacity hoarding against competitors. Those who meet their volumes get the deposit back; those who fall short forfeit it. Over-volume purchases trigger fresh pricing talks. Around 80% of capacity-reservation agreements covering more than ten photonics-SOI customers are expected to be signed within a week or two, with the remainder inside a month, according to a Reuters interview with Soitec CEO Laurent Remont.

Photonics-SOI revenue is on track to more than double this financial year from slightly above $100M to more than $200M, a figure Remont now calls "absolutely a floor" rather than a ceiling. Soitec itself has a reminder in the same conversation that substrate bets do not always pay off: the company wrote down a French cleanroom originally built for silicon carbide by 41M euros, roughly $47.7M, last year. The facility is now part of the underused cleanroom space Soitec plans to retool for photonics-SOI instead.

Soitec says it does not need a new fab until around 2029, with the next leg of growth covered by adding tools to existing cleanroom space, including the reabsorbed silicon-carbide plant. UBS and Morgan Stanley both maintain buy ratings on the stock on the photonics transition. Pricing power in the AI buildout has been moving down the stack from chips to packaging to substrates; the deposit-and-forfeit structure is the first time the substrate layer has had to admit demand is outrunning supply.

The only on-the-record source for the contract mechanics is the CEO, UBS's 95% share is a broker estimate rather than a measurement, and Soitec's silicon-carbide writedown shows the company has had substrate bets that did not pay off. The contracts being signed in the next two weeks are the test.