Sourcing doped indium antimonide wafers from China

Duty on doped indium antimonide wafers

Heading 3818 covers chemical elements doped for electronics in discs, wafers or similar forms, and chemical compounds doped for electronics. Doped indium antimonide wafers fall within the other doped compounds line, 3818 00 90 00. The table shows wafer variants using this same tariff line.

Read from the UK Trade Tariff on 1 October 2026, this line carried 0% duty for goods from China. The supplied tariff record lists no anti-dumping or countervailing duty, suspension or attached import control for this line. These tariff findings do not determine chemical compliance obligations.

Confirm the composition, doping and processing stage against the commodity code guidance. For the wider heading, see the doped gallium arsenide wafer guide.

Specify the dopant and electrical test conditions

Specify indium antimonide composition, dopant identity, conductivity type, carrier concentration, mobility and resistivity. Agree the measurement temperature and test method, so results can be compared. Also define crystal orientation, diameter, thickness, thickness variation, bow, edge finish and which surfaces are polished. For epitaxial growth, agree surface preparation and acceptance criteria with the receiving process team.

UK REACH generally applies to chemical substances on their own, in mixtures or in articles. Ask a chemicals adviser to assess the supplied wafer form, composition and intended use. Where substance or mixture classification and labelling is needed, HSE says the work must be carried out by someone with scientific competence. Obtain the supplier's composition and safe-handling information for that assessment.

Worked duty example

Illustrative example, not a quote: Illustrative trial order of 5 doped indium antimonide wafers under 3818 00 90 00, invoiced at £2,500 free on board, with £200 of freight and insurance to the UK. The customs value is £2,700. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £2,700, so it is £540. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.

Inspection checklist

Identity: match the wafer and carrier labels to the dopant, crystal orientation and lot identifiers on the order and test report.

Electrical data: compare carrier concentration, mobility and resistivity with the agreed limits, using the specified measurement temperature and method.

Geometry and surface: check sampled wafers for thickness variation, bow, cracks, edge chips, scratches and residue against the agreed acceptance criteria.

Packing: check that individual wafers are restrained in clean carriers, protected from contact and movement, and traceable to their lot. Record damage before unpacking further; use the quality inspection guide to agree the inspection scope.

What goes wrong

A wafer can match the ordered dimensions yet fail the electrical specification. Reports without measurement conditions are difficult to compare, and a dopant or lot substitution can undermine process trials. Ask for lot-specific results and approve a sample against the receiving process before accepting a repeat order.

Edge chips, scratches and surface residue can make wafers unsuitable for the planned processing. Loose carriers can also allow damage in transit. Agree surface inspection, packing and rejection criteria before dispatch, then keep affected wafers separate while the supplier reviews the arrival evidence.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.