MBE Components, Valved Sulfur Cracking Source VCS

VCS

Valved Sulfur Cracking Source


VCS-300
  • Provides cracked or uncracked sulfur flux

  • Suitable for other materials like Cs, Pb, K as well (modifications on request)

  • Flux modulation and on/off control by motorized valve

  • Source capacities from 300 up to 9600 cm³

  • Water-cooled assembly

  • Excellent flux uniformity due to beam shaping nozzle

  • Avoids loss of sulfur during system bakeout

VCS-300 Valved Sulfur Cracking Source with 300 cm³ crucible and DN63CF (O.D. 4.5") mounting flange

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The VCS is a valved sulfur cracker, employed in high efficiency CIS solar cell growth and other II-VI semiconductor material deposition applications.

Sulfur beam pressure is generated in a heated large capacity metal crucible with inserted quartz liner. The sulfur flow rate is controlled and switched on/off by a specially designed sulfur-resistant valve whose outlet opens into an injection tube that includes an independently heated cracking zone. The temperature within the cracking zone can be adjusted to generate either uncracked or cracked sulfur. The use of a beam shaping nozzle at the end of the injection tube provides excellent flux uniformity on the substrate.
The valve design features a large cross-section orifice which allows very good pumping properties of the reservoir. Its robust wide angle valve design effectively eliminates the risk of locking, which is a frequently observed problem with needle valves.

Technical details of the construction have been optimized to meet the specific requirements of research deposition applications and MBE systems. Simple system integration and excellent long-term run-to-run stability have been demonstrated. Different crucible sizes of 300 cm³ or 500 cm³ are offered on DN63CF (O.D. 4.5”).

For very large capacity industrial sources please see VSS. The figure on the right-hand side shows an industrial version, applied in sulfurization processes in thin film solar cell manufacturing.

VCS-6000 Large capacity reservoir

Large capacity reservoir of the VSS-9600 for industrial applications

Application

The VCS Valved Sulfur Cracking Source has been designed for the controlled evaporation of sulfur. It can be used for II-VI semiconductor thin film research and solar cell manufacturing. Other possible applications are, for example, post-growth sulfurization processes.

MBE-Komponenten provides support in the design of customer-specific research or production systems in order to achieve a customized source geometry, optimized for specified layer uniformity and most efficient deposition material consumption.

Co-deposition processes can be simulated on request. The simulations are based on geometric and Monte Carlo method calculations. Typical results include the lateral layer thickness distribution and material composition for multiple material co-deposition processes on semiconductor wafers as well as on large area substrates.

Technical Data

Type VCS-300 VCS-500
Crucible capacity
300 cm³ 500 cm³
Length of injector tube
250 to 400 mm 250 to 400 mm
In-Vacuum diameter
(w/o cooling shroud)
see drawing below contact us
Operating temperatures
- crucible zone
- cracker (no cracking) - cracker (cracking)
150 to 300°C
400°C
800-1000°C
150 to 300°C
400°C
800-1000°C
Outgassing temperature
(crucible / cracker)
300° / 1200°C 300° / 1200°C
Bakeout temperature 250°C 250°C
Water cooling main body
injector tube (option)
main body
injector tube (option)
Valve opening time
1 sec 1 sec
Heater circuits
- crucible + valve
- cracker
- crucible + valve
- cracker
Thermocouples W5%Re/W26%Re (typeC)
2 thermocouples
(crucible-valve / cracker)
W5%Re/W26%Re (typeC)
2 thermocouples
(crucible-valve / cracker)
Valve control manual or motor drive MVCU manual or motor drive MVCU



Dimensions

Schematic drawing VCS

Schematic drawing of the Valved Sulfur Cracker Source VCS

(drawing shows
VCS-300 with VDAP adapter)