FUSED QUARTZ
Quartz Diffusion Tube
High-purity fused quartz diffusion and oxidation tubes for semiconductor furnaces — straight bore, flanged, and bell-end configurations for 4" to 12" wafer processes.
Custom dimensions and specifications available upon request.
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: < 0.05 mm
- Weld integrity: He leak rate < 1×10⁻⁹ mbar·L/s at each weld
- 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 < 1100°C | Grade 1 (Natural) | Cost-effective; < 20 ppm total metals |
| CVD / processes where ppb metals critical | Grade 2 (Synthetic) | < 50 ppb total metals |
| Thermal shield / outer tube | Grade 3 (Opaque) | High IR reflectivity; lower cost |
Quality & Documentation
Every diffusion tube ships with:
- Material certificate — XRF/ICP-OES purity data
- Dimensional inspection report — OD, ID, wall, length, bow
- He leak test certificate (flanged tubes)
- Visual inspection report — bubble, inclusion, surface defect check
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
Ready to order or need a custom size?
Submit your drawing or specifications — we respond within 24 hours.