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H-flux

Atomic Hydrogen Source

Thermal hydrogen cracker



H-flux Atomic Hydrogen Source with optional shutter


The new H-flux Atomic Hydrogen Source* works by thermally dissociating hydrogen in an electron bombardment heated fine tungsten capillary (thermal hydrogen cracker). By bouncing along the hot walls the molecular hydrogen is cracked to atomic hydrogen. This is e.g. very useful for in-situ, damage free cleaning of residual oxygen prior to sample coating (MBE) or analysis. Other applications are in surface modifications appreciating the high reactivity of atomic species.


The H-flux Atomic Hydrogen Source is UHV compatible and mounted on a NW35CF (2.75"OD) flange, making the source an easy retrofit to existing vacuum systems.

Applications:

Atomic Hydrogen can be used in surface science and thin film technolgy ( MBE, GSMBE ) mainly for the following applications:

  • damage free in situ cleaning e.g GaAs, InP, Ge and Si. Removal of residual oxygen and carbon
  • Low temperature cleaning
  • Surfactant - improvement of layer properties during growth
  • post growth surface treatment/improvement
  • chemical passivation and surface reconstruction
  • annealing of amorphous silicon

Key Features:

Key features of the H-flux Atomic Hydrogen Source are the zero residual ion current and almost 100% cracking efficiency, due to the superior and unique Bertel design. Integral watercooling is included as standard to minimise heat load in the system and outgassing. A manual shutter is available as option.

  • Zero residual ion current
  • Almost 100% cracking efficiency 
  • Integral water-cooling as standard to minimise heat load in the system and outgassing
  • Capable of operation in UHV without differential pumping
  • Thermocouple and PID controller as standard for reproducible and constant operation
  • Filament made of standard Tungsten wire for inexpensive on-site replacement


Specifications:

Typical operating conditions: the flux of Hydrogen atoms at 10-9 mbar in a chamber with typical pumps at a distance of 10cm is ca. 5x1013 atoms/cm².

Source properties:

Gas Flow: 10-5 sccm to 1sccm
Operating Pressure: <10-10 to 10-5 mabr
Hydrogen Flux:~5x1013 atoms/cm² @ 10cm distance and 10-9 mbar
Beam Divergence:~15° half angle

 

Hardware Source:

High Voltage:1,2kV (max) adjustable
Beam current:50mA (max) adjustable
Power: 60W (max) adjustable via voltage and current
In vacuum length: 190mm
In vacuum diameter: 34mm (max)
Mounting Flange: NW40CF (2.75")
Leak valve:required (see option)
Integral cooling: water
Bakeable:200°C


Power Supply:

  • HV connection via over-specified high voltage feedthrough with matching connector potted onto the cable and screw-on retaining sleeve for high-level user safety
  • All feedthroughs are user demountable for on-site service/repair 
  • Filaments are easily replaced and user fabricated from 0.3mm tungsten wire of near zero running costs 
  • Water-cooled copper jacket to minimise radiated heat and outgassing 
  • Water connection via 1/4” Swagelok fittings 
  • Gas connection via mini-Conflat (NW16CF) flange 
  • Additional spare NW 16CF ports on the multiport for future upgrade with the options listed above 
  • 19" rack mount, 3U high, 230VAC/50Hz (115VAC/60Hz optional)

Options:

Manual shutter: can be operated and closed within the ID of an DN40CF port.
Shutter actuator: for remote/computer controlled shutter operation.

References:

"Simple source of atomic hydrogen for ultrahigh vacuum applications", U. Bischler and E. Bertel; J. Vc. Sci. Technol. A 11(2), Mar/Apr 1993
"Quantitative characterisation of a highly effective atomic hydrogen doser", C. Eibl, G. Lackner, and A. Winkler. J.; Vac. Sci. Technol. A 16(5), Sep/Oct 1998.


Atomic Hydrogen Source (front view)




* In cooperation with Prof. Dr. E. Bertel of the University of Innsbruck

In the interests of continuous product development, specifications are subject to change without notice.

Quick links to other major tectra products:

Electron Beam Evaporator - 4-pocket e-beam evaporator - Plasma Source - Atomic Hydrogen Source - Sputter Gun - Mini-Coater Deposition System - Sputter-Coater
   
  contact: contact: Dipl.-Ing. Andreas Gati
tectra GmbH
Reuterweg 65
D-60323 Frankfurt
phone: Germany (0) 69 - 72 00 40
fax: Germany (0) 69 - 72 04 00
email: info@tectra.de
home: www.tectra.de
  last update: 26.8.06
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