Fused Quartz
Quartz Diffusion Tube
Fused quartz diffusion and oxidation tubes for semiconductor furnaces — straight bore, flanged, and bell-end configurations reviewed against furnace and process requirements.
Custom dimensions and specifications available upon request.
View Quartz Tubes & Furnace Tubes CategoryTechnical Specifications
| Parameter | Value |
|---|---|
| Material | Fused quartz GE-124 equivalent / Synthetic silica HPFS equivalent |
| Purity | ≥ 99.99% SiO₂ (Grade 1) / ≥ 99.9999% SiO₂ (Grade 2) |
| OD Tolerance | ±0.5 mm |
| Wall Thickness Tolerance | ±0.3 mm |
| Length Tolerance | ±1 mm |
| Bow (per 1000 mm) | < 1 mm |
| Surface Finish (Inner) | Ra ≤ 1.6 μm |
| He Leak Rate (Flanged) | Leak testing can be arranged when specified |
Quartz Diffusion Tube
Quartz Diffusion Tubes
Diffusion tubes are the primary reaction chamber in horizontal and vertical furnace systems used for thermal oxidation (SiO₂ growth), dopant diffusion (boron, phosphorus, arsenic), LPCVD thin film deposition, and high-temperature annealing. The tube’s material purity and dimensional accuracy directly affect wafer uniformity and contamination levels.
Product Configurations
Straight-Bore Open Tube
The simplest configuration — a cylindrical tube with both ends open. Used where end caps, flanges, or caps are provided by the furnace OEM.
| Parameter | 4” Process | 6” Process | 8” Process | 12” Process |
|---|---|---|---|---|
| Nominal OD | 125 mm | 175 mm | 225 mm | 325 mm |
| Nominal ID | 118 mm | 168 mm | 218 mm | 318 mm |
| Wall thickness | 3.5 mm | 3.5 mm | 3.5 mm | 3.5 mm |
| Standard length | 1200 mm | 1500 mm | 1500 mm | 1800 mm |
| Max length | 2000 mm | 2000 mm | 2000 mm | 2000 mm |
Flanged Tube
One or both ends fitted with precision-ground flanges for O-ring or metal face-seal connections to furnace end caps.
- Flange OD: Matched to furnace OEM face specification
- Flange face flatness: Reviewed against the mating interface requirement
- Weld integrity: Leak testing can be arranged for relevant flanged tubes when specified
- Available flange types: Flat face, raised face, custom
Bell-End Tube
One end formed into a rounded bell — provides an aerodynamically smooth closed end for single-ended loading. Common in vertical furnace designs.
- Bell radius matched to tube OD
- Wall uniformity at bell: ±10% of nominal wall thickness
- Available in all standard OD sizes
Material Grade Selection
| Application | Recommended Grade | Why |
|---|---|---|
| Standard diffusion / oxidation below typical quartz service temperatures | Grade 1 (Natural) | Cost-effective; material certificate can be reviewed by source |
| CVD / processes with tighter purity requirements | Grade 2 (Synthetic) | Trace-metal limits should be confirmed by material source and order scope |
| Thermal shield / outer tube | Grade 3 (Opaque) | High IR reflectivity; lower cost |
Quality & Documentation
Documentation for diffusion tubes can be discussed based on order requirements:
- Material certificate — may be available depending on material source and order scope
- Dimensional inspection report — OD, ID, wall, length, bow, or other drawing-critical dimensions
- Leak test record — can be arranged for relevant flanged or welded tubes when specified
- Visual inspection notes — bubble, inclusion, or surface condition checks as required
Custom Specifications
Drawing-based custom tubes are our specialty. Common custom features include:
- Side ports and gas injection inlets
- Step-bore profiles (different ID at each end)
- Extra-thick wall for high-pressure applications
- Non-standard lengths and diameters
- Opaque outer / transparent inner composite tube
Related Products
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Fused quartz wafer boats for horizontal and vertical diffusion furnaces, with slot count, pitch, and wafer format reviewed against drawings or samples.
Custom Quartz Flange for Fused Quartz Assemblies
Custom fused quartz flange components fabricated to drawings for quartz tube assemblies, laboratory systems, semiconductor equipment and thermal-processing applications.
Quartz Baffle & Insert
Custom-machined fused quartz baffles, liners, and thermal shields for semiconductor furnace tubes, diffusion systems, and CVD reactors.
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