China prices Japanese deposition gas out of its own fabs with a 99.2% deposit

The person who has to answer for this is whoever signs the DCS purchase order at a Chinese fab, because an import duty bills the buyer, not the exporter ^[15]. Post a 99.2% deposit against an invoice of 100 and the shipment clears at 199.2 ^[20]. That is the arithmetic behind the word prohibitive ^[1], applied to a gas the fab consumes continuously rather than buys once ^[5].

The rate table closes the obvious door. Shin-Etsu Chemical draws 99.2%, and so does every other Japanese exporter ^[4]. The one name below the top rate is Denal Silane, the Denka and Air Liquide joint venture, at 80.8% ^[4], which buys 18.4 points of relief ^[21] and still leaves four fifths again on top of the invoice.

Switching suppliers outside Japan means running a qualification project, not cutting a purchase order. Deposition chemistry is unforgiving about contamination, and a fab that changes supplier buys months of qualification work ^[18]. So the pitch and the practice come apart in a familiar way: a bill of materials can list two approved vendors while the line has only ever run material from one.

The beneficiary here is clear. Tangshan Sunfar Electronic Materials, a Chinese producer, filed the application on 8 December 2025 ^[11], and a protective duty exists to hand a domestic producer the market at a price importers cannot match. The heaviest users on the buying side are Chinese memory makers, because memory stacks far more deposited layers than logic does ^[16]. CXMT, the country's largest DRAM producer, is contesting a US listing in the Washington courts while its input costs rise by order of its own government ^[17].

Instrument choice matters as much as the rate. Export controls on gallium, germanium, graphite and rare earths announce themselves as policy ^[8]. An anti-dumping case arrives with a petitioner, an investigation, a determination and a comment period, all recognised under WTO rules, and the European Union ran the same instrument against Chinese electric vehicles ^[9].

The petition landed roughly a month after Prime Minister Sanae Takaichi suggested in November that Japan's military could intervene in a Taiwan contingency, and Beijing has imposed dual-use export controls on Japanese firms in the months since ^[12]. The record does not establish that one caused the other, and petitions of this kind take months to prepare ^[13].

Estimates of Japan's global market share vary too widely to support any claim about world supply. Estimates of Japan's share range from under a tenth to three quarters with no primary source behind any of them, in a market the Associated Press calls highly competitive ^[7]. AP does describe Japan as the leading producer of ultrapure dichlorosilane for chip fabrication ^[3]. The demonstrated exposure is narrower than a global chokepoint and harder to fix than a price rise: Chinese buyers of Japanese DCS, paying near-double landed cost, with a qualification calendar in the way.

For anyone keeping a single-source register, the useful column is a date rather than a vendor name, and the date is the last time production material actually shipped from the second source. Where that cell is empty, the input has one supplier whatever the approved vendor list says, and a filing in a ministry gazette can idle the line as neatly as a refused licence ^[10]. Chinese memory fabs are reading that column now. European PC buyers, whose desktop shipments are already falling after three quarters of sharp DRAM rises, meet the result later in the price of a finished module rather than in any shortage of gas ^[19].