- Applicable in most UHV systems up to 1400°C
- Compatible with all standard MBE crucibles
- Crucible capacities from 2 to 200 cm³
- Most effective heating system with excellent reliability and long lifetime
- Hot lip, cold lip and dual filament designs
- Optional on-flange integrated cooling shroud and shutter
- ISO-K cells available for HV applications
Introduction
The Standard Effusion Cell WEZ is designed for evaporation or sublimation of a variety of elements and compounds, e.g., typical III-V MBE materials such as Al, Ga, or In, in the temperature range from 700°C up to 1400°C. The WEZ is chiefly used for thin film growth and sample preparation, but may also be applied as a doping source (e.g. for Si or Be).
Standard filament SF , hot lip filament HL , cold lip filament CL and dual filament DF heaters are available, meeting differing requirements of the evaporation materials. Each filament assembly is built up of tantalum wires supported by PBN rings. This wire heater concept provides for excellent temperature uniformity within the crucible, an effective heating even at the crucible lip, and allows the use of differently shaped crucibles. Due to the few contact points between filament wire and supporting rings, decomposition of PBN at operation temperature is effectively minimized. Further advantages of the heater concept are its excellent reliability, long-term stability and extended lifetime, compared with Ta foil heaters.
In addition to the standard crucible material PBN (pyrolytic boron nitride), WEZ cells can also be equipped with PG (pyrolytic graphite), refractory metal, or Al2O3 crucibles.
Application
WEZ standard effusion cells are usually employed in research type UHV systems for elements and compounds that require operation temperatures between c. 700°C and 1400°C. Typical evaporants are, amongst others, Ga, In, Al, Si, Be, Cu, Ag, Au, CaF etc.
The typical fields of application for WEZ cells are sample preparation, thin film growth and MBE. For instance, the compact design of the WEZ 40-10-22-KS makes it particularly suited to material deposition on small samples in surface analysis systems. Cells tailored to the different evaporation material requirements are offered for MBE applications, e.g., hot lip or dual filament cells for Ga and In, or cold lip cells for Al.
WEZ cells can also be used for doping applications. For this purpose effusion cells with conical crucibles are available. Please refer to DEZ Doping Effusion Cells .
Technical Data
| Filament | Ta wire heating filament: standard (SF), hot lip (HL), cold lip (CL), dual (DF) |
| Thermocouple, Temperature sensor (other types on request) | Type C |
| Operating temperature | 700-1400°C |
| Outgassing temperature | max. 1500°C |
| Bakeout temperature | 250°C |
| Cooling / water cooling | integrated water cooling or separate cooling shroud |
| Crucibles | 2-200 cm³; PBN, PG, Al2O3 crucibles (other materials on request) |
| Options | integrated water cooling (K), integrated rotary shutter (S) |
Specific Data
For general information on CF mounting flanges see Flange and Gasketdimensions.| Product | Flange [CF] | Nominal capacity [cm³] | Lip diameter [mm] | Cooling | Shutter | Filament type | Thermocouple type | UHV dimensions [mm] specify L with order | |
|---|---|---|---|---|---|---|---|---|---|
| WEZ | 16 | 2 | 16 | SF, CL | C | LxxxD16 | |||
| WEZ | 40 | 2 | 16 | SF, CL | C | LxxxD34 | |||
| WEZ | 40 | 2 | 16 | S | SF, CL | C | LxxxD34 | ||
| WEZ | 40 | 2 | 16 | K | S | SF, CL | C | LxxxD34 | |
| WEZ | 40 | 10 | 22 | S | SF, CL, HL, DF | C | LxxxD34 | ||
| WEZ | 40 | 10 | 22 | K | S | SF, CL, HL, DF | C | LxxxD36 | |
| WEZ | 40 | 25 | 33 | S | SF, CL, HL, DF | C | LxxxD33 | ||
| WEZ | 40 | 35 | 34 | S | SF, CL, HL, DF | C | LxxxD34 | ||
| WEZ | 40 | 12 | 37 | SF, CL | C | LxxxD37 | |||
| WEZ | 40 | 35 | 37 | SF, CL, HL, DF | C | LxxxD37 | |||
| WEZ | 40 | 60 | 37 | SF, CL, HL, DF | C | LxxxD37 | |||
| WEZ | 63 | 35 | 34 | K | S | SF, CL, HL, DF | C | LxxxD57 | |
| WEZ | 63 | 35 | 37 | S | SF, CL, HL, DF | C | LxxxD56 | ||
| WEZ | 63 | 60 | 37 | S | SF, CL, HL, DF | C | LxxxD56 | ||
| WEZ | 63 | 60 | 37 | K | S | SF, CL, HL, DF | C | LxxxD57 | |
Example: WEZ 40-10-22-KS-HL-C-P-L220D36 is a standard effusion cell on DN40 CF-flange for a 10 cm³ crucible (lip Ø 22mm), with integrated water cooling shroud, shutter, hot lip filament, type C thermocouple, PBN crucible, in-vacuum length 220mm and diameter 36mm.
