China Opens Anti‑Dumping Investigation Into Japan‑Origin Dichlorosilane

China’s Ministry of Commerce (MOFCOM) has formally initiated an anti‑dumping investigation into imports of dichlorosilane (DCS) originating from Japan, a key high‑purity specialty gas widely used in semiconductor manufacturing. China’s expanding use of trade remedy measures to protect domestic suppliers amid intensifying geopolitical and economic tensions with Japan and other major trading partners.

The subject of the probe is dichlorosilane (chemical formula SiH₂Cl₂), a colorless, flammable, toxic gas with purity above 99% that serves as a major precursor in thin‑film deposition processes during chip fabrication. These processes include epitaxy and the growth of silicon nitride, silicon oxide, silicon carbide, and polysilicon films, all of which are critical layers in logic, memory, analog and other advanced semiconductors.

MOFCOM’s announcement clarified that the product falls under China’s tariff code 28539090, but that only dichlorosilane of this specification is within the scope of this investigation.

The petition requesting the probe was filed in December 2025 by Tangshan Sunfar Electronic Materials Co., Ltd., a Chinese producer of electronic chemicals, asserting that Japanese exports had dominant market share and pricing power in China’s DCS market.

Investigation windows and timeline

MOFCOM set the following review periods:

• • Dumping investigation period: July 1, 2024 – June 30, 2025
  • Injury investigation period: January 1, 2022 – June 30, 2025

According to China’s anti‑dumping regulations, the probe is expected to conclude by January 7, 2027, with an allowance for up to a six‑month extension under special circumstances.

Allegations From Domestic Producers

According to MOFCOM and filings from the Chinese applicant:

• • Import volumes of Japanese DCS generally increased between 2022 and 2024.
  • At the same time, export prices from Japan dropped cumulatively by about 31% over the same period.
  • These imported goods are alleged to have entered the Chinese market at prices below fair value, exerting downward price pressure and harming the operating margins and competitiveness of domestic producers.

The Chinese industry claims these conditions resulted in market disruption, inventory build‑ups, underutilized capacity, and employment effects in its own dichlorosilane sector

Potential Outcomes and WTO Context

If MOFCOM ultimately determines that dumping and material injury have occurred, China may impose anti‑dumping duties on imports of Japanese DCS, calibrated to offset alleged price distortions. Duties could materially raise the cost of Japanese‑sourced dichlorosilane in China, reducing the price advantage Japanese suppliers have enjoyed and boosting the competitiveness of domestic equivalents.

Affected Japanese exporters, including major electronic gas producers such as Shin‑Etsu Chemical, Taiyo Nippon Sanso and Air Liquide Japan, could see their market share in China decline if duties are substantial. These firms together account for a significant share of global dichlorosilane production and exports.

Japan or other impacted exporters could challenge any adverse ruling at the World Trade Organization (WTO), as has occurred in past trade disputes with China over other commodities.

Dichlorosilane is an essential gas in semiconductor fabrication and any disruption to supplies or changes in pricing can ripple through costs for chipmakers in both China and abroad. While China seeks to strengthen domestic capability in electronic gases and reduce reliance on foreign suppliers, Japanese producers have historically supplied much of the high‑purity material China needs.

Trade measures of this kind can also affect downstream industries that rely on a stable and competitively priced supply of precursor gases, including logic, memory, and analog semiconductor production, sectors central to both consumer electronics and advanced technology supply chains.