Semiconductor Raw & Refined Materials

Semiconductor fabrication begins far upstream of the fab floor, at mines, smelters, and chemical refineries. Raw materials -- quartzite, gallium, germanium, indium, tungsten, tantalum, rare earths -- must be extracted, refined, and purified to electronic grade before they can enter the semiconductor supply chain. The refining step is often more technically demanding and geographically concentrated than the extraction step. China controls not only significant mining output for many of these materials but -- more critically -- an even larger share of refining capacity. Refining to semiconductor-grade purity is capital-intensive, energy-intensive, and subject to export controls that have been actively applied since 2023.

Mined Raw Materials: Source & Semiconductor Use

Material	Primary Source	Mining Mechanism	Semiconductor Use	Strategic Risk
Quartzite (SiO2)	High-purity silica deposits; US (SD, TX, MN), Norway (Drag), Brazil, UK	Open-pit quarrying; crushed and sorted for SiO2 purity (>99.5% for semiconductor grade)	Reduced to MG-Si → polysilicon → wafers; quartz crucibles for CZ crystal growth	Spruce Pine (NC) is primary global source of ultra-high-purity quartz for crucibles; The Quartz Corp (Imerys/Norsk JV) controls this niche
Gallium (Ga)	Byproduct of bauxite/aluminum refining; ~80% from China	Not directly mined; recovered from Bayer process liquor during aluminum refining; ~35 tonnes/year produced outside China	GaAs and GaN compound semiconductors; TMGa MOCVD precursor	Chinese export licensing since Aug 2023; byproduct supply cannot scale independently of aluminum production
Germanium (Ge)	Byproduct of zinc ore processing and coal fly ash; ~60% from China	Recovered from zinc smelter residues; also from coal combustion fly ash at select plants	SiGe CVD channels (GeH4 precursor); IR optics; fiber optics; zone-refined substrates	Chinese export licensing since Aug 2023; directly affects GeH4 availability for advanced transistors
Indium (In)	Byproduct of zinc and tin smelting; ~57% refined in China	Recovered from zinc smelter flue dusts and residues; small volumes from tin smelting	InP substrates; ITO transparent electrodes; TMIn MOCVD precursor	Chinese export licensing since Feb 2025; AI-driven InP photonics demand accelerating against constrained supply
Tungsten (W)	Primary tungsten ore (scheelite, wolframite); >80% from China (USGS)	Hydrometallurgical extraction from ore concentrate; ammonium paratungstate (APT) intermediate	Tungsten plug fill (WF6 CVD); contacts; sputtering targets for barrier layers	Chinese export licensing since Feb 2025; every advanced logic node uses W interconnects; no practical substitute
Tantalum (Ta)	DRC (~40% mine output), Rwanda, Australia; Ningxia Orient (CN) major processor	Coltan (columbite-tantalite) ore mined and processed; DRC artisanal mining raises conflict mineral concerns	DRAM/logic capacitors (Ta2O5 dielectric); BEOL diffusion barriers (TaN sputtering targets)	No Chinese export controls; conflict mineral risk from DRC sourcing; OECD due diligence requirements for smelters
Copper (Cu)	Chile (~28% global), Peru, DRC, US; widely distributed primary production	Open-pit and underground sulphide ore mining; flotation concentration; pyrometallurgical smelting	BEOL damascene interconnects; electroplating; packaging; sputtering targets for seed layers	Low -- geographically distributed; electrolytic refining to 5N+ is well-established at multiple global sites
Rare Earths (Ce, Nd, Dy, others)	>90% processing in China; mine production from China, Australia (Lynas), US (MP Materials)	Bastnasite and monazite ore mining; multi-stage hydrometallurgical separation of individual REEs	NdFeB magnets in fab equipment motors; CeO2 ceria CMP abrasive; laser gain media	Seven REEs under Chinese export licensing since Apr 2025; rare earth separation is the critical concentration step -- China controls >90% of refined output

Refining to Electronic Grade

Raw mined materials are unusable in fabs at the purity levels they come from the ground. The refining step -- converting smelter-grade metal or chemical intermediate into electronic-grade material -- is often the most technically demanding and geographically concentrated step in the upstream supply chain. Purity requirements increase with each process node: copper at 5N+ (99.999%) for advanced BEOL interconnects, tungsten at 4N-5N for sputtering targets, germanium at 7N+ for substrates and optical applications. The table below maps key materials through their refining steps.

Material	Starting Grade (Smelter)	Refining Method	Electronic Grade Purity	Key Refined Forms	Primary Refined Suppliers
Polysilicon (Si)	MG-Si ~98-99% (from quartzite arc furnace)	Siemens process (TCS CVD on heated rods) or FBR (fluidized bed, monosilane); multi-stage distillation of TCS intermediate	10N-11N (99.9999999999%) for semiconductor grade; 9N-10N for solar mono	Polysilicon rods (Siemens); granular polysilicon (FBR); broken chunks for CZ crucible loading	Wacker Chemie (DE), Hemlock (US), Tokuyama (JP) for semiconductor grade; Tongwei, GCL TECH (CN) dominate solar grade
Germanium (Ge)	Smelter byproduct; ~3-4N after initial chemical concentration	Zone refining (RF induction heating passes a narrow molten zone along a Ge rod; impurities segregate toward ends; successive passes achieve 7N+)	7N+ (99.99999%) for substrates and IR optics; higher for some radiation detector applications	Zone-refined germanium ingots; GeH4 (germane) CVD precursor synthesized from Ge metal; GeCl4 for fiber optics	Umicore (BE), Yunnan Germanium (CN); GeH4 precursor from industrial gas majors (Linde, Air Products)
Gallium (Ga)	Crude gallium from Bayer liquor; ~99.9% (3N)	Electrolytic refining; fractional crystallization; zone refining for highest purity grades	6N+ (99.9999%) for GaAs/GaN applications; 7N for some compound semiconductor epitaxy	High-purity gallium metal; TMGa (trimethylgallium) MOCVD precursor; GaN crystal feedstock	Chinalco (CN, dominant); Recylex (FR); Nyrstar (BE); TMGa precursor from Nouryon (NL), Entegris (US)
Copper (Cu)	Anode copper from smelting; ~99.5% (3N5)	Electrolytic refining in copper sulfate bath; copper deposits on cathode at 99.99%+ (4N); further purification to 5N+ for semiconductor via zone refining or additional electrorefining	5N (99.999%) for sputtering targets and electroplating seed layers in advanced BEOL	Copper sputtering targets (bonded to backing plate); copper electroplating bath chemistry; copper foil for packaging	Mitsubishi Materials (JP), Honeywell (US), Plansee (AT) for semiconductor sputtering targets; copper electroplating chemistry from MacDermid Enthone (US), Atotech (DE)
Tungsten (W)	Ammonium paratungstate (APT); reduced to W metal powder at ~3N-4N	Hydrogen reduction of APT to W powder; powder metallurgy (pressing and sintering) to form dense targets; further purification via electron beam melting for highest-purity grades	4N-5N for sputtering targets; WF6 CVD precursor synthesized from W metal + F2	W sputtering targets (PVD barrier/liner deposition); WF6 CVD precursor for tungsten plug fill	Plansee (AT), Materion (US), H.C. Starck (DE, now Masan) for W targets; WF6 from Linde (IE), Air Products (US)
Tantalum (Ta)	K-salt (potassium tantalum fluoride) or tantalum oxide from coltan processing; 3N-4N	Sodium reduction (metallothermic) or electron beam melting of oxide to metal; powder metallurgy to sputtering target form; conflict mineral smelter certification required (OECD 3TG)	4N-5N for sputtering targets; tantalum capacitor powder at distinct high-surface-area spec	Ta sputtering targets for TaN diffusion barrier PVD; Ta2O5 for capacitor dielectric; Ta powder for DRAM capacitors	Ningxia Orient Tantalum (CN); Global Advanced Metals (AU/US); Plansee (AT); KEMET/Yageo (capacitor grade)
Rare Earth Oxides (Ce, Nd)	Mixed rare earth carbonate from ore processing; individual REE separation required	Solvent extraction (liquid-liquid extraction in series of mixer-settler stages) separates individual REEs; China controls the processing chemistry and infrastructure at scale	CeO2 at 4N+ for CMP abrasive; NdFeB magnet alloy at production grade; La2O3 for specific laser and optical applications	CeO2 ceria powder (CMP slurry abrasive); NdFeB magnet alloy ingots and sintered blocks; REE-doped laser crystals	AGC/Seimi Chemical (JP, ceria for CMP); MP Materials (US, mining + early-stage separation); Lynas (AU, processing in Malaysia); NdFeB magnets from Shin-Etsu Chemical (JP), TDK (JP), and Chinese producers

Zone Refining: Germanium & Silicon

Zone refining is the purification technique used to reach the highest purity levels for germanium and, in the Float Zone process, silicon. A narrow molten zone is created by an RF induction coil and passed along the length of the material rod from one end to the other. Most impurities have a lower solubility in the solid phase than in the liquid phase -- so as the molten zone moves, impurities are swept along with it toward one end of the rod. After multiple passes, the center of the rod reaches very high purity while impurities concentrate at the ends, which are then cut off and discarded. Germanium zone refining reaches 7N+ (99.99999%) after a sufficient number of passes. Silicon float zone growth (described in the Specialty Silicon Wafers page) uses the same physics to produce FZ silicon at below 10¹⁵ oxygen atoms/cm³.

Sputtering Targets: The Fab-Ready Form

Many refined metals (tungsten, tantalum, copper, titanium, cobalt, ruthenium) are delivered to fabs as sputtering targets -- precisely machined discs or rectangles of high-purity metal bonded to a backing plate, installed in physical vapor deposition (PVD) chambers. The target is bombarded by argon ions, which sputter metal atoms onto the wafer surface to deposit thin films for barrier layers, seed layers, and gate metals. Target purity directly affects deposited film quality: metallic impurities at the ppb level in the target can cause device failures. Target grain size, texture, and bonding integrity also affect deposition uniformity. Producing semiconductor-grade sputtering targets requires the full refining chain (electrolytic purification + optional zone refining + powder metallurgy + precision machining + ultrasonic bonding to backing plate) from a small number of qualified suppliers -- Plansee, Materion, Honeywell, and Mitsubishi Materials are the primary Western providers.

Supply Chain Outlook

The refined materials supply chain is where China's dominance in raw material extraction is reinforced by an equally dominant position in refining infrastructure. China controls not just the mine output for gallium, germanium, and rare earths, but the refining capacity that converts those minerals into semiconductor-usable forms -- sputtering targets, MOCVD precursors, ceria polishing powders, and NdFeB magnets. Building alternative refining capacity outside China requires capital, process chemistry expertise, environmental permitting, and qualification time measured in years. Export controls on raw materials (gallium, germanium, indium, tungsten) translate directly into constraints on refined forms (TMGa, GeH4, TMIn, WF6) because the refining supply chain is integrated. Western governments' critical minerals initiatives aim to build alternative refining capacity, but the gap between current non-Chinese refining output and semiconductor industry demand remains large and will not close quickly.

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