The Veeco Downward-Looking SUMO Source is a dual filament source with an asymmetric SUMO crucible, uniquely designed to accommodate a molten charge in a downward-facing source port. The narrow orifice is offset to contain the melt, while a tapered exit cone provides excellent flux uniformity. This novel crucible shape is available only with Veeco’s patented SUMO technology.
Hot-lip heating in the exit cone region prevents charge recondensation and minimizes Group III-related oval defects. This design and position of the base heater filament is tailored to the non-uniform distribution of charge material in the crucible for optimal flux stability. This source is not for use with aluminum.
Downward-looking source ports enable users to expand the total number of Group III sources available on an MBE system with downward looking source ports. Redundant sources increase the total charge capacity for the most commonly used materials, and allow for rapid switching between different flux settings by using separate sources for each desired flux. The Downward-Looking SUMO Source also offers increased charge capacity for molten source materials in shallow upward-facing ports. For example, a 175g Downward-Looking SUMO Source in the shallow upward-looking port on a GEN III System has a capacity of 425g of gallium while a standard 400g SUMO would have a capacity of 49g in the same port.
The exit cone design assures flux uniformities comparable to those achieved with a system’s original Group III sources. Standard 1% uniformity has been demonstrated across a 2” wafer in a MOD GEN II System.