Valved Cracker for Selenium
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Valved Cracker for Selenium 500cc Valved Cracker for Selenium • Patented design with more than 50 in the field • 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 • Utilized by leading II-VI research groups worldwide with more than 50 in the field Description The Veeco Valved Cracker for Selenium is used by leading II-VI research groups worldwide. Its multiple heating zones can be operated to generate a cracked or uncracked selenium flux. An all-metal needle valve regulates the gas flow from the crucible through the conductance tube to the growth module. The conductance tube is constructed of tantalum for resistance to chemical attack from selenium vapor. With recent enhancements, the Mark V Valved Cracker for Selenium 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 The Veeco Valved Cracker for Selenium is available in 500cc and 1200cc sizes for compatibility with various MBE systems. The exit nozzle is customized to the specific MBE system for excellent flux uniformity across the wafer or platen. Principle of operation for the Selenium Valved Source (1200cc shown above). 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 is heated to keep the valve clear and prevent recondensation of material. An integrated nozzle optimizes the flux uniformity across the substrate while minimizing material waste.

A Veeco SMC-II Automated Valve Positioner is recommended for use with this source for reliable, automated control of the needle valve. Flux response to valve opening and closing for the Se Valved Source. Flux data taken at 10-second intervals. Data courtesy of J.F. Schetzina, North Carolina State University. The Veeco Valved Source for Selenium offers convenience and flux control unrivaled by any standard source. 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...

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 Standard 2.25”/57mm With Water-Cooling 2.7”/69mm External Dimensions Contact Veeco Crucible Dimensions/Interior Fill Port Diameter Typical Operating Temperatures Bulk Zone Present, but not used during normal operation Bellows Zone Conductance Zone Cracking Zone Maximum Outgassing Temperatures (Power Requirements) Bulk Zone...

Valved Cracker for Selenium 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. Please 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, GEN10, GEN20 and...