Pyrolytic Boron Nitride (PBN) Crucible for MBE & Vacuum Evaporation

Pyrolytic Boron Nitride Crucible Applications

• OLED/Vacuum Thermal Evaporation

  ✅Key Advantages

  1. Flux Uniformity — conical or insert-assisted geometry supports consistent film thickness across substrates.
  2. Clean Evaporation — low outgassing interior helps maintain chamber baseline and reduce particle risk.
  3. Non-Wetting Behavior — improves changeover hygiene and material utilization.

  ✅ Problem Solved

  A display coater reduced rework events after switching to non-wetting PBN interiors and matched lip geometry; line reported more stable evaporation rate during long runs and smoother cleanouts between materials, improving planned uptime across a quarter.

• MBE Platforms(Universities /Institutes /Pilot)

  ✅Key Advantages

  1. Stable Beam Flux — consistent cone and wall profile aids source repeatability during long growth cycles.
  2. Dimensional Repeatability — ID/OD and lip tolerances allow comparable runs across parallel sources.
  3. UHV Compatibility — low outgassing surface supports background cleanliness for sensitive stacks.

  ✅ Problem Solved

  A research platform standardized 20–120 cc crucibles with common lips and heights; cross-tool substitution improved scheduling, and flux stabilization trimmed trial iterations during recipe transfer.

• Optical Coatings

  ✅Key Advantages

  1. Material Release — non-wetting interior aids stable wetting angles during metal/oxide melts.
  2. Thermal Management — anisotropic PBN helps guide heat for steady evaporation.
  3. Geometry Options — cylindrical for steady draw, conical for directional shaping.

  ✅ Problem Solved

  A coating shop reduced post-run clean time and maintained targeted deposition rates over longer batches after adopting cylindrical PBN crucibles with tuned wall thickness for their source.

Pyrolytic Boron Nitride Crucible Usage Instructions

Proper installation and handling of a PBN crucible directly affect material utilization, flux stability, and service life. The following guidelines are designed for users in MBE, PVD, OLED evaporation and high-temperature vacuum systems.

• Installation & Pre-Use Preparation

  1. Check compatibility with the effusion cell/evaporation source (shoulder diameter, lip height, mounting groove).
  2. Inspect visually for edge chips, pore contamination, or cracks under light—especially at the lip and inner surface.
  3. Clean handling only: use powder-free gloves and avoid touching the inner surface with bare hands.
  4. Dry-fit alignment before heating to confirm clearance for thermocouples, shutter and crucible holder.
  5. Initial bake-out recommended: gradually heat to remove adsorbed moisture (e.g., 150–200 °C for 1–2 hours in vacuum or inert gas).

• Operating During Evaporation/ MBE/ Deposition

  1. Material loading
  a. Fill factor should be 50–80% of crucible volume to avoid overflow or thermal shock.
  b. Use non-metal tweezers or ceramic tools when placing material.
  
  2. Heating process
  a. Ramp temperature slowly (≤ 10 °C/min) for first use to prevent thermal stress.
  b. Stabilize at the target evaporation temperature before opening the shutter.
  c. Monitor crucible wall temperature vs. source material vapour pressure.

  3. Evaporation control
  a. For MBE: maintain stable flux rate (via beam flux monitor, quartz crystal, or ion gauge).
  b. For organics (OLED): avoid overheating above the decomposition point to reduce carbon buildup.
  c. For metals: ensure non-wetting behaviour remains; if material starts to stick, stop heating and inspect.

• Cooling & Post-Operation Handling

  1. Allow the crucible to cool naturally to < 200 °C before any movement.
  2. Do not quench or expose to airflow while hot—this can induce cracks.
  3. Record material residue height, weight of crucible, or deposition rate for process tracking.
  4. If switching materials, gently remove remaining material—avoid scraping the inner PBN layer.

• Cleaning & Maintenance

  1. Recommended methods

  a. Dry removal only: remove remaining chunks using soft plastic or PBN tools.
  b. No chemical immersion: PBN can absorb some liquids and crack upon reheating.
  c. No abrasive blasting or sharp scrapers: this damages the CVD layer and leads to future crack initiation.

  2. If contamination occurs

  a. Light organic residue → low-temperature oxygen plasma or slow oxidation (<500 °C) if the chamber allows.
  b. Metal adhesion → mechanical removal only; replace crucible if inner surface becomes rough or wettable.

• Storage & Protection

  1. Store each crucible in an individual clean pouch or foam cavity to prevent lip contact.
  2. Use labeling or a QR code for material type and number of cycles.
  3. Avoid humid or dusty environments; if moisture is absorbed, perform a low-temperature bake-out before reuse.
  4. Do not stack crucibles directly; keep upright to avoid edge fractures.

Pyrolytic Boron Nitride Crucible Properties FAQ

1. Q: What makes a PBN crucible different from regular BN or alumina crucibles in vacuum evaporation?
   A: PBN crucibles are produced by chemical vapor deposition (CVD), not powder sintering, which results in a fully dense, pore-free structure with ≥99.99% purity. Unlike alumina or hot-pressed BN, they exhibit lower outgassing, non-wetting behavior to molten metals and organics, and maintain stability in UHV and effusion cell environments.
2. Q: Can a PBN crucible be used for both metal evaporation and organic OLED materials?
   A: Yes. PBN crucibles are chemically inert and non-wetting to most metals (Al, Au, Ag, In, Mg) and organic molecules used in OLED evaporation. Users must, however, control temperature to avoid thermal decomposition of organics and prevent carbonization on the crucible surface.
3. Q: How long does a PBN crucible typically last in MBE or evaporation systems?
   A: Service life depends on thermal cycling, source material, and cleaning method. In well-controlled MBE systems, a PBN crucible can last 100–300 heating cycles. Lifetime is shortened if exposed to thermal shock, aggressive scraping, or metal infiltration due to overheating.
4. Q: Why does flux drift occur even when using a high-purity PBN crucible?
   A: Flux drift usually results from uneven material loading, oxide formation on melt surfaces, misaligned thermocouples, or poor crucible/material wetting. If PBN's non-wetting property is lost (e.g., due to surface contamination), material may climb the wall and alter emission angles.
5. Q: Can PBN crucibles be reused after evaporation? How should they be cleaned?
   A: Yes, they are reusable. Cleaning must be dry only—using plastic or PBN tools to remove residual material. No chemical soaking, ultrasonic cleaning, or sandblasting. Organic residues can be treated with low-temperature oxygen cleaning (<500 °C), while metal residues must be mechanically removed or the crucible replaced if inner surface roughness increases.
6. Q: Is PBN electrically insulating at high temperatures inside an effusion cell?
   A: Yes. PBN maintains high electrical resistivity (~10¹³–10¹⁶ Ω·cm) from room temperature up to ~1500 °C, making it suitable for heater-coil isolation and preventing current leakage within effusion cell assemblies. In contrast, graphite liners become conductive and react at high temperature.

Pyrolytic Boron Nitride Crucible Reviews

• ⭐️⭐️⭐️⭐️⭐️
  The PBN crucible with a conical interior stabilized our OLED evaporation rate and simplified cleanouts between materials.
  Hannah Lee — Process Engineer, Vistalux Displays
• ⭐️⭐️⭐️⭐️⭐️
  We standardized on MBE PBN crucibles across two tools; dimensional repeatability improved recipe transfer.
  Martin K. — Lab Manager, Northbridge Materials Institute
• ⭐️⭐️⭐️⭐️⭐️
  ADCERAX supported a shaped PBN crucible with an insert. Even at a higher unit cost, reduced rework and fewer pan changes offset spend.
  Diego Romero — Sourcing Lead, OptiCoat Systems
• ⭐️⭐️⭐️⭐️⭐️
  We started using a pyrolytic boron nitride (PBN) crucible in our MBE system. Flux became more stable and the cleaning time dropped, especially with gallium and indium sources.
  Alina Novak — Production Supervisor, Luminate Coatings