Intermetallic (BN-TiB2) E-Beam Crucibles

Crucible damage often results from improper handling during the electron-beam (e-beam) evaporation process. Two primary causes include incorrect ramp/soak settings and abrupt power shutdowns.

1. Incorrect Ramp/Soak Settings

The e-beam evaporation process typically relies on two ramp/soak power levels to gradually heat materials for deposition. Mismanagement of these levels can lead to significant issues, including crucible cracking.

• Ramp/Soak Transition:
  When the material reaches deposition temperature, power control shifts from ramp/soak settings to a PID loop that manages the e-gun power supply and quartz crystal controller. If the second ramp/soak power level (ramp2/soak2) is not closely aligned with the power needed to maintain the desired deposition rate (e.g., 1 Ångström/sec), the PID loop may struggle to stabilize.
  • Wild Power Fluctuations: Power can oscillate dramatically (+90% to 0%) before stabilizing, causing the material to repeatedly liquefy and condense. These rapid phase changes can lead to cracks in the crucible.
  • Preventive Measures: Setting ramp2/soak2 power levels near the required deposition power minimizes PID adjustments and prevents rapid liquefaction and condensation cycles.

2. Abrupt Power Shutdowns

A sudden shutdown of the power supply or insufficient ramp-down time post-deposition can also stress the crucible.

• Rapid Solidification:
  When the melt solidifies too quickly, it creates mechanical stress on the crucible liner. This stress can lead to cracking or breakage.
  • Solution: Gradually reduce power after deposition to allow the melt to cool and solidify evenly.

Final Thoughts

Intermetallic crucibles are robust tools for material deposition processes, but careful management of e-beam evaporation parameters is crucial to their longevity. Adhering to proper ramp/soak levels and avoiding abrupt power shutdowns are key to preventing damage. MetalsTek’s customizable intermetallic crucibles provide the flexibility and reliability needed for a wide range of applications.