GUIDE FOR SOURCE SELECTION
How to select an MBE source:

The selection of a cell depends first on the type of materials to be evaporated and the application.
The following is a classification of the different ADDON sources by Vapor Pressure Level and elements for most of the common MBE materials
High Vapor Pressure Materials
(source temperature: < 750° C)		 Recommanded source type
As, P, S, Sb, Te & Se Valved Cracker Cells
Other Materials
Very High Vapor Pressure Materials
(source temperature:50° C - 400° C)
Polymers, Organics Very Low Temperature cell
Hg, As, Cd, Se Very Low Temperature cell or Mercury cell
Zn Zn source
Other Materials Very Low Temperature cell
Medium Vapor Pressure Materials
(source temperature: 700°C – 1400°C)
Al "Hot Zone/Cold Zone" cell or "Cold Lip"
Ga, In "Double Zone" or "Hot Lip" cell
Other Materials "Hot Lip" if condensation / convection are a problem
Minicell
Dopants
(for Low & Medium Vapor Pressure Materials)
Be, Dy, Er, Ge, Si, Sn, Y, PbTe, SnTe Dopant Effusion cell
C C Sublimation Doping source
N, O Plasma Source
P, As (in Si) Si Doping Sublimation source
Low Vapor Pressure Solid Materials
(source temperature > 1350°C)
Transition Metals, Boron High Temperature cell
Rare Earths High Temperature cell
Silicon Si Deposition Sublimation source
Gases for Nitride growths, CBE or MOMBE or GSMBE, substrates preparation or doping
Atomic N, O, H & radicals Thermal Cracking or RF Plasma Source or Valved RF
Hydrides High Temperature thermal cracker or injector
Organo-metallic compounds Low Temperature thermal cracker or injector
Ammoniac Low Temperature thermal cracker or injector


If you wish to evaporate a material which is not specified above please refer to the Guide for Source Selection by Element or Compound to find the appropriate source.
If you have any further questions please do not hesitate to contact us directly.

When the proper type of cell is selected the following criteria are often to be considered:

1 Crucible type and dimensions
Please refer to page Crucible Type to select the proper crucible according to the material to be evaporated
( ie Group III determine the uniformity of the deposition ) , the substrate dimensions and the MBE geometry.

2 Port dimensions, system geometry
If the MBE system is a well known commercial one it is generally sufficient to know the port size and its location to select the proper source.
In case of doubt Addon can supply you with additional information about the compatibility of your choice with your system.

If your system is a custom designed one it is useful to consider the following. Do not hesitate to contact us we will be happy to help you make the best selection.
• Flange size and type
• Tube internal dimension ( Tube ID)
• Available length between the flange seal ( knife) and the shutter (Referred to as Cell Length in this brochure)
• Source to substrate incidence angle and distance
• Integrated shutter and/or an integrated cooling needs
• Availability of existing control, power supplies and cables. If a new unit is needed see Electronics below.

ADDON can install most of its sources on non-standard or uncommon flanges upon request at a reasonable charge
(a customer drawing could be required).

3 Electronics:
ADDON cells are designed to allow the user to use his existing controls and power supplies whenever possible . If a new power system is necessary, the ADDON models are recommended. Using the most up to date microelectronic components, they are simple to use, effective and economic. Seven metre long cables comes with the power unit. Addon integrates only high quality PID controllers and DC well regulated and stable power units ( SCR’s types are not allowed in Europe)
Electrical connectors used on most of our cells are the Addon Uniplug. It integrates power and compensated TC connections. These plugs are fully bakeable and mate directly to the standard power unit cable connectors used by major MBE manufacturers. ( Riber, Varian/Intevac, VG Semicon and EPI). No dismounting of original cable connectors is necessary.