Valved Cracker for Sulfur 500cc Valved Cracker for Sulfur • Generates either cracked or uncracked S flux • Provides flux modulation and on/off control • Large source capacity • Utilizes a nozzle for excellent flux uniformity and reduced material waste • Prevents loss of source material during system bakeout • Used by leading II-VI research groups worldwide with more than 30 in the field Description The Veeco MBE Valved Cracker for Sulfur offers convenience and control unrivaled by any standard source. The large capacity refractory metal crucible is heated to generate a sulfur beam flux (consisting of Sn where n=8,7,6,5,3,2). Gas flow is regulated through a refractory metal needle valve into an independently heated cracking zone. The temperature of the cracking zone may be adjusted to generate either uncracked sulfur flux or a beam of smaller sulfur species. The cracking zone is constructed of quartz rather than a refractory metal due to sulfur’s corrosive nature. With recent enhancements, the Mark V Valved Cracker for Sulfur incorporates a nozzle that provides excellent flux uniformity and reduced material waste. This improvement in material utilization results in: • Material cost savings • Longer campaigns • Shorter system cleaning time • Less hazardous waste generation • Reduced memory effects • Lower particulate levels and flaking • Reduced system window coating A Veeco SMC-II Automated Valve Positioner is recommended for use with this source for reliable, automated control of the needle valve. Principle of operation for the Valved Cracker for Sulfur. Source material is loaded into the large capacity crucible and heated. A needle valve in the conductance tube regulates the amount of evaporant which enters the growth chamber. Valve position is controlled with either a manual micrometer or an Automated Valve Positioner. The conductance zone temperature is controlled so as to produce beams of either cracked or uncracked material and an integrated nozzle optimizes the flux uniformity across the substrate while minimizing material waste.

Performance and Benefits The Valved Cracker for Sulfur is used by leading II-VI research groups worldwide. Control over the growth process is optimized using a needle valve for nearly instantaneous flux modulations and complete flux shut-off. The source may be idled continuously at operating temperature without depleting the charge material. With mechanical flux control, rather than the thermal control used for conventional open sources, the charge capacity may be arbitrarily large without limiting the responsiveness of the source. Flux response to valve opening and closing for the Valved Cracker...

Product Specifications Source Characteristics Maximum Charge Capacity Minimum Mounting Flange Size Standard 2.75”/70mm With Water-Cooling 4.5”/114mm Standard 4.5”/114mm With Water-Cooling 6”/152mm Cracking Head Length Standard 1.41”/36mm With Water-Cooling 2.2”/56mm External Dimensions Contact Veeco Crucible Dimensions/Interior Fill Port Diameter Standard 2.2”/56mm With Water-Cooling 2.7”/69mm Typical Operating Temperatures Bulk Zone Cracking Zone Maximum Outgassing Temperature (Power Requirements) Bulk Zone Cracking Zone Standard for bulk zone. Optional cooling coil or jacket for cracking zone...

Valved Cracker for Sulfur Selection Guide Typical Source Commonly Used Indicated By “X” System 500cc X Veeco sources are also available for use on systems from Eiko, Anelva, Ulvac, SVTA, and DCA, as well as custom chambers. Contact Veeco for details. Solutions for a nanoscale world.™ Compound Semiconductor • MBE Operations 4900 Constellation Drive, St. Paul, MN 55127 USA Phone: (651) 482-0800, Fax: (651) 482-0600 www.veeco.com/mbe © 2009 Veeco Instruments Inc. All rights reserved. (3-09) GEN200 and GEN2000 are registered trademarks and GEN II, GEN III, GEN930, GEN 10, GEN20 and Solutions for...