Quartz Crucible | Fused Quartz Crucible Manufacturer & Supplier — FGQuartz China

A fused quartz crucible is a high-purity bowl-shaped vessel manufactured from fused silica — silicon dioxide in its amorphous glass form — used primarily as the containment vessel in the Czochralski (CZ) crystal pulling process for growing monocrystalline silicon ingots. In the CZ process, polysilicon feedstock is melted inside the quartz crucible at temperatures exceeding 1414°C, and a seed crystal is drawn upward from the melt surface while rotating, allowing a single-crystal silicon ingot to solidify on the seed. The quartz crucible holds the silicon melt for the entire duration of the crystal pull — a process that can last many hours — while simultaneously acting as the primary source of controlled oxygen input into the growing crystal.

The quartz crucible is the most critical consumable in the CZ silicon production sequence. Its purity determines whether transition metals are introduced into the silicon melt during the pull; its structural integrity determines whether the crucible survives the sustained thermal and mechanical stresses of the process without catastrophic failure; and its inner surface characteristics determine the oxygen dissolution rate and therefore the oxygen concentration profile of the grown crystal.

Beyond semiconductor CZ silicon production, fused quartz crucibles are used in directional solidification furnaces for multicrystalline silicon ingot casting, as laboratory quartz crucibles for high-purity material melting in analytical and materials science research, and in speciality crystal growth processes for optical and electronic materials. In every application, the defining requirement is the same: a thermally stable, chemically inert, high-purity container that does not contaminate the material being processed at extreme temperatures.

The purity of the fused quartz crucible directly determines the metallic contamination level introduced into the silicon melt during the CZ crystal pull. Transition metals — iron, chromium, nickel, copper — dissolve from the crucible inner wall into the silicon melt at process temperatures and are subsequently incorporated into the growing crystal lattice, where they create deep-level recombination centres that reduce minority carrier lifetime and degrade device electrical performance. FGQuartz sources fused silica raw material with very low transition metal content appropriate for semiconductor and solar-grade silicon production, and verifies incoming material purity before committing it to crucible production. This traceability from raw material to finished crucible is the foundation of consistent crystal purity across all production batches.

The bubble structure within a fused quartz crucible wall influences its mechanical behaviour during the CZ process in two important ways. Bubbles near the inner surface of the crucible, which is in contact with the silicon melt, can rupture as the crucible wall softens at process temperature, releasing gas into the melt and creating turbulence that disturbs the crystal growth interface. Bubbles distributed through the outer wall of the crucible affect its mechanical strength and its resistance to deformation under the compressive load of the molten silicon charge. FGQuartz controls the bubble distribution in its quartz crucibles through the arc fusion manufacturing process and raw material selection, producing a crucible structure with a dense inner layer appropriate for direct melt contact and controlled outer layer porosity that provides the thermal insulation and structural compliance required for the CZ process.

A CZ silicon crystal pull subjects the quartz crucible to one of the most thermally demanding service environments of any industrial component. The inner surface of the crucible is in contact with molten silicon at temperatures above 1414°C, while the outer surface, held in a graphite susceptor, experiences a different temperature gradient and is also subject to radiative heating from the susceptor walls. The crucible must maintain its shape and structural integrity throughout this environment for the full duration of the pull, which can exceed twenty hours for large-diameter ingots. Fused silica maintains structural competence in this environment because its softening point is well above the silicon melting point, and its near-zero thermal expansion coefficient means that the thermal gradients through the crucible wall do not generate the cracking stresses that would fracture a higher-expansion material.

Quartz crucibles are consumable items — they are used for one or more crystal pulls and then replaced. The number of pulls achievable per crucible before replacement is a significant cost driver in CZ silicon production. Crucible service life is determined by the rate at which the inner surface dissolves into the silicon melt, the structural deformation of the crucible body under sustained thermal load, and the accumulation of mechanical damage from the repeated loading and unloading of the silicon charge. FGQuartz optimises crucible wall thickness distribution and inner surface characteristics to extend service life in both single-pull and continuous-feed CZ configurations, supporting the maximum number of pulls per crucible that the process conditions and crystal quality requirements allow.

Wall thickness uniformity around the circumference and along the height of the crucible is critical for consistent oxygen dissolution and stable crystal growth conditions. A crucible with non-uniform wall thickness has a non-uniform thermal resistance around its perimeter, creating temperature asymmetries in the silicon melt that drive asymmetric melt convection patterns. These asymmetric flows produce non-uniform oxygen and dopant concentration distributions in the grown crystal, resulting in radial resistivity variations in the silicon wafers that can cause device performance non-uniformity across the wafer. FGQuartz controls wall thickness uniformity through the arc fusion manufacturing process and post-fusion dimensional inspection, producing crucibles with consistent wall geometry that supports uniform melt conditions throughout the crystal pull.

Beyond metallic impurities, the quartz crucible also contributes oxygen to the silicon melt through dissolution of the inner surface — a process that is deliberately controlled rather than minimised, since controlled oxygen in CZ silicon provides the bulk micro-defect gettering that improves device yield in downstream processing. The oxygen concentration achieved in the grown crystal depends on the crucible inner surface dissolution rate, the melt convection pattern, and the crystal pull rate. FGQuartz produces quartz crucibles with inner surface characteristics appropriate for the target oxygen concentration of the crystal grade being grown — from low-oxygen CZ grades for power device applications to higher-oxygen grades where precipitation-mediated gettering is the production strategy — ensuring that the crucible supports, rather than compromises, the oxygen engineering strategy of the crystal grower.

The Czochralski process for monocrystalline silicon ingot production is the dominant application for fused quartz crucibles globally. CZ silicon ingots are the substrate for the large majority of integrated circuits and power devices manufactured worldwide. The quartz crucible is the direct container of the silicon melt during the crystal pull and has no substitute at the production volumes and crystal sizes required by the semiconductor industry — no other affordable material survives sustained contact with molten silicon at the temperatures required for the full duration of the crystal pull. FGQuartz supplies CZ quartz crucibles for semiconductor-grade silicon production in standard diameters from 12 inches to 32 inches, covering the full range of crystal puller platforms from small research pullers to large-diameter production systems.

Beyond CZ silicon, fused quartz crucibles are used as the containment vessel for melting a range of high-purity inorganic materials in research and industrial contexts. The combination of high melting point stability, chemical inertness to molten metals and ionic compounds, and the absence of metallic contamination from the crucible wall makes fused quartz the preferred crucible material for melting high-purity metals, salts, and oxide compounds where contamination from the crucible would alter the composition or properties of the melt. Speciality crystal growth processes — including Bridgman-Stockbarger growth of compound semiconductors, floating zone silicon, and lithium niobate crystal growth — use quartz crucibles or quartz-lined vessels in the process equipment surrounding the growth zone.

Monocrystalline silicon for high-efficiency PERC, TOPCon, and HJT solar cells is grown by the same Czochralski process as semiconductor-grade silicon, using the same type of fused quartz crucible. The purity requirements for photovoltaic-grade CZ silicon are stringent — transition metal contamination from the crucible creates carrier recombination centres in the silicon that reduce minority carrier lifetime and directly lower solar cell conversion efficiency. For solar cell technologies targeting efficiencies above 23%, the quality of the quartz crucible is a meaningful variable in the cell efficiency distribution across the silicon production lot. FGQuartz supplies quartz crucibles for solar CZ silicon production in the diameter range matched to current large-format solar ingot puller platforms, including continuous-feed CZ configurations that require the crucible to survive multiple silicon recharge cycles.

In materials science research and advanced manufacturing, laboratory quartz crucibles serve as the high-temperature reaction vessels for synthesising and processing materials that require contamination-free environments at temperatures above the capability of platinum, alumina, or graphite crucibles. High-purity metal oxide synthesis, glass frit preparation, solder alloy melting, and geochemical reference material preparation are performed in laboratory quartz crucibles where the ultra-low metal blank of fused silica — significantly lower than borosilicate glass or ceramic crucibles — ensures that the crucible does not contribute trace elements that would falsify the analytical result or alter the composition of the synthesised material.

The quartz crucible is the central structural element of the Czochralski crystal growth system around which the puller furnace, heating system, gas flow management, and crystal diameter control systems are all designed. The crucible diameter and height determine the silicon charge weight, the melt depth available for the crystal pull, and the thermal geometry of the furnace hot zone. Crystal pullers are designed around specific crucible diameter standards — 18-inch, 20-inch, 22-inch, 24-inch, 28-inch, and 32-inch are the main commercial standards — and the quartz crucible must fit the graphite susceptor and rotation drive of the specific puller model without play or interference. FGQuartz produces crucibles matched to the leading crystal puller platforms from major equipment manufacturers and also to custom puller designs from emerging silicon producers developing new CZ systems.

Custom diameter and height to fit any crystal puller susceptor geometry

Wall thickness profile engineering for target oxygen dissolution rate and crucible service life

Bubble distribution control for semiconductor-grade and photovoltaic-grade applications

Inner surface treatment options matched to low-oxygen, standard-oxygen, and high-oxygen CZ silicon grades

Custom surface treatment and preparation for precision laboratory quartz crucible applications

Full process consultation from an experienced quartz crucible manufacturer — from specification to first article approval