Hot Zone / Cold Zone Cells

HOT ZONE
COLD ZONE CELLS

Model Number

Prevents the formation of the very low vapor pressure aluminum nitrides on the crucible walls
Extra negative temperature gradient
Very long term flux stability and perfect day-to-day reproducibility
Two independently heated and cooled zones
Easy to install on all MBE systems (several models available)
Only one power supply
Uses the well known low cost PBN crucibles
Increases the useful capacity of Al cells

A NEW ALUMINUM EFFUSION CELL FOR ALUMINUM NITRIDE & AlGaN GROWTH

Temperature gradient along crucible height

This curve shows the AlN growth rate evolution versus run number. It illustrate the run to run reproductibility of the Aluminium flux. After 31 runs, the Al flux is modified by less than 2%. (Here a small 25 cc capacity crucible was used.)
(31 runs are equivalent to approximatively 12 µm of growth)
The Al cell was used to growth Al _0,13GaN/GaN MQWs.
(Courtesy of CHREA Lab Valbonne)

ALUMINUM EVAPORATION UNDER AMMONIA AND NITROGEN
The use of ammonia as a nitrogen precursor to grow Aluminum Nitrides and AlGaN by MBE is a very promising and powerful technique. Conventional, Standard and even "Cold Lip effect" effusion cells are not adapted to work in an ammonia or Nitrogen gas environment. Ammonia or N reacts with Aluminum at the crucible mouth and produces nitride compounds. This induces a creeping of the Aluminum melt. Overflow of the molten charge is then observed. This phenomenon occurs quickly and prevents use of a conventional aluminum cell for more than a few runs. Several groups reported aluminum crucible breakage and cell disintegration under these conditions.

ADDON has designed a completely new high thermal gradient cell specially adapted to work under ammonia.

DESIGN
The ADDON cell uses two distinct thermal zones, the zone at the bottom of the crucible is heated by radiation while the zone at the tip of the crucible is cooled down by thermal transfer to a water panel. This allows a larger temperature gradient than a typical ‘’cold lip’’ design. Many users of this new Al cell have reported a far better ease of use and better results. The flux stability and run-to-run reproducibility is greatly improved. Aluminum cell temperature idling between runs is generally not possible when ammonia is used in the MBE, as the ammonia pressure is much too high if the cryocooling is stopped. Aluminum cell cooling is then the only solution, the New Al cell can be room temperature cooled every day and reheated without trouble.

See also Cold Lips Cells

MBE Manufacturer	MBE Model Number	Min Connecting Flange	Crucible Capacity (cc)	Cell Model Number	Crucible Model Number
RIBER	1000/32/2300	DN40CF 2,75" (70mm)	25	GRT25RB3	835025
	EPINEAT COMPACT 21	DN63CF 4" (114 mm)	30	GRT30RE	863030
	EPINEAT COMPACT 21	DN100CF 6" (152 mm)	30	GR30TRE	863030
	48/49	DN150CF 10" (254 mm)	200	GRT200R8	700200
VG All dopant cells have Integrated Water Cooling	V80	DN63CF 4" (114 mm)	30	GRT30VG8W	863030
	V90	DN63CF 4" (114 mm)	30	GRT30VG9W	963030
	V100	DN100CF 6" (152 mm)	200	GRT200VG1W	700200
Varian / Intervac	Gen II	DN40CF 2,75" (70mm)	16	GRT16VA2	735016
Varian / Intervac	Mod Gen II	DN63CF 4" (114 mm)	30	GRT30VA3	863030
Others and manufacturers not listed above if needed Integrated Water Cooling is a factory option*	Flange Size	DN40CF 2,75" (70 mm) or higher	16	GRT16AD	735016
	Flange Size	DN63CF 4" (114 mm) or higher	30	GRT30AD	863030
	Flange Size	DN100CF 6" (152 mm) or higher	30 200	GRT30AD GRT200AD	863030 700200
	Flange Size	DN150CF 10" (254 mm) or higher	30 200	GRT30AD GRT200AD	863030 700200
*Do not hesitate to contact ADDON if your system is not listed above or if your system is a custom designed one.

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