The Veeco Low Temperature Dual Filament Source for MBE uses two independent heaters to control the temperature variation along the length of the crucible. The primary heater filament heats most of the crucible. The tip filament heats just the mouth region of the crucible to compensate for the greater radiative heat loss in this area. The source is operated in hot-lipped mode to eliminate material recondensation at the crucible orifice, which can lead to source occlusion and beam shadowing.
The Low Temperature Dual Filament Source is enclosed in a heat-shielding package designed for optimal source responsiveness and stability in the operating range of 100-750°C. Temperature stability is critical with high vapor pressure materials, since even a small temperature variation produces a dramatic change in the flux.
The Low Temperature Dual Filament Source is also available in the high-performance SUMO design. See the “Low Temperature SUMO Source” data sheet for further details.
The Low Temperature Dual Filament Source is precisely tailored to the demands of evaporating high vapor pressure materials.
Dual Filament “hot-lip” heating prevents condensation at the crucible orifice. This has been proven effective with a number of “difficult” materials including antimony, tellurium, and lead compounds.