Cold Lip SUMO Source for Aluminum

The Best Source for Aluminum Evaporation in MBE

Eliminate damage and get thickness uniformity and flux stability with Veeco’s patented Cold Lip SUMO® Source—the optimal MBE source technology for Group III (particularly Al) material evaporation. It features a unique, patented crucible with a cylindrical reservoir and small tapered orifice, and provides large capacity, excellent flux uniformity, and minimal shutter flux transients or long-term depletion effects.

  • Patented design with more than 350 in the field
  • Increased capacity
  • Eliminates damage from Al creep
  • Extremely stable operation minimizes day-to-day flux calibration
  • Greatly reduces shutter flux transients
  • Low background impurities
  • PBN crucible construction optimizes material quality

The SUMO Source is the optimal source technology for Group III materials. The cold-lip source, designed specifically for aluminum evaporation, prevents material overflow commonly caused by aluminum wetting of PBN.

The SUMO design features a dual filament heater and a custom heat-shield cap tailored to a uniquely shaped crucible. The heaters and heat shielding are positioned for efficient heating of the crucible body with an intentional cold lip beyond the crucible orifice. Any aluminum which creeps beyond the orifice will freeze on the large lip without damaging the source. With dual filaments operated in “cold-lip” mode, the temperature gradient may be adjusted to optimize the aluminum flux uniformity for the specific source port and source charge level.

The patented crucible features:

  • A cylindrical reservoir for large charge capacity and minimized long-term depletion effect
  • A small tapered orifice for optimal flux distribution and negligible shutter flux transients
  • A wide lip in the cold zone to protect the source by freezing any aluminum that may creep out of the source. With proper operation, aluminum doesn’t creep beyond the crucible orifice. Specific to nitride applications, where the problem of aluminum creep is particularly severe, Veeco offers a material-specific extended-lip SUMO Crucible. The extension of the PBN lip on the crucible enhances the crucible cold zone and provides additional containment of molten aluminum and nitride compounds
  • PBN crucible construction optimizes material quality

SUMO Sources are available in a variety of sizes compatible with virtually all MBE systems.

Performance and Benefits

SUMO Sources provide the largest available Group III charge capacity without sacrificing material quality or source performance. Facilities worldwide have demonstrated excellent material quality with good thickness uniformity across the substrate.

Benefits include:

  • Large charge capacity. Compared to the original Group III sources from other vendors, the aluminum charge capacity may be more than doubled.
  • Good uniformity. SUMO Sources are designed to meet or exceed the thickness uniformity (±1%) achieved in most MBE systems with the originally recommended sources.
  • Long-term flux stability. With its unique shape, the SUMO crucible minimizes the long-term depletion effects commonly seen with conical crucibles. The SUMO presents a constant melt surface for more consistent and reproducible day-to-day operation. A constant beam flux is maintained with smaller and less frequent temperature changes.
  • Reduced shutter-related flux transients. The melt surface, recessed behind the small orifice of the SUMO crucible, is shielded from most reflected radiation. Heat reflected back from closed shutters is diffused by the PBN crucible and the heat-shielding cap.
  • Excellent material quality. PBN crucible construction and small crucible orifice, coupled with efficient dual filament heating, reduces the thermal load on the surrounding system and leads to lower background impurities in the grown layers.

The SUMO Source, operated in cold-lip mode, is the optimal aluminum source for most applications. A standard Dual or Single Filament Source may be preferable in cases where a smaller charge capacity is acceptable and fast ramping of source temperature is critical.

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