Standard Effusion Cell WEZ

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 type	Ta wire heating filament: standard ( SF ), hot lip ( HL ), cold lip ( CL ), dual ( DF )
Thermocouple	W5%Re/W26%Re (type C)
Operating temperature	700-1400°C
Outgassing temperature	max. 1500°C
Bakeout temperature	250°C
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 )

Crucibles

In order to ensure compatibility with all MBE systems, WEZ cells are conveniently available with a wide range of standard crucibles of different shapes and sizes. Most of the crucibles are cylindrical, but conical shapes with taper angles up to 10° are available as well.
The most commonly used crucible material is PBN; other materials are available as required. Please refer to the Selection Guide or inquire for detailed recommendations. For information on crucibles see Crucibles .

The second number of the product code is the nominal crucible capacity [in cm³], the third number indicates the lip diameter of the crucible. Please specify crucible material, if not PBN.

Dimensions

Schematic drawing WEZ — Schematic drawing of the Standard Effusion Cell WEZ (drawing shows WEZ 40-10-22-KS)

Specific Data

For general information on CF mounting flanges see Flange and Gasketdimensions .

Product	CF flange	Nominal capacity [cm³]	Lip diameter [mm]	Cooling	Shutter*	Filament type	Thermocouple type	Crucible material**	UHV dimensions*** [mm]	max. electrical [W]/[A]	Power supply product code	Crucible product code
WEZ	16 -	2 -	16 -			SF¹ -	C -	P -	LxxxD16	155 / 8	PS 30-10	CRU 2-16
WEZ	40 -	2 -	16 -			SF¹ -	C -	P -	LxxxD34	120 / 7	PS 30-10	CRU 2-16
WEZ	40 -	2 -	16 -		S -	SF¹ -	C -	P -	LxxxD34	160 / 8	PS 30-10	CRU 2-16
WEZ	40 -	2 -	16 -	K	S -	SF¹ -	C -	P -	LxxxD34	170 / 8	PS 30-10	CRU 2-16
WEZ	40 -	10 -	22 -		S -	SF² -	C -	P -	LxxxD34	240 / 8	PS 30-10	CRU 10-22
WEZ	40 -	10 -	22 -	K	S -	SF² -	C -	P -	LxxxD36	240 / 9	PS 30-10	CRU 10-22
WEZ	40 -	25 -	33 -		S -	SF² -	C -	P -	LxxxD33	450 / 14	PS 40-19	CRU 25-33
WEZ	40 -	35 -	34 -		S -	SF² -	C -	P -	LxxxD34	470/ 12	PS 40-19	CRU 35-34
WEZ	40 -	12 -	37 -			SF¹ -	C -	P -	LxxxD37	465 / 15	PS 40-19	CRU 12-37
WEZ	40 -	35 -	37 -			SF² -	C -	P -	LxxxD37	495 / 14	PS 40-19	CRU 35-37
WEZ	40 -	60 -	37 -			SF² -	C -	P -	LxxxD37	580 / 11	PS 40-19	CRU 60-37
WEZ	63 -	35 -	34 -	K	S -	SF² -	C -	P -	LxxxD57	490 / 11	PS 40-19	CRU 35-34
WEZ	63 -	35 -	37 -		S -	SF² -	C -	P -	LxxxD56	555/ 14	PS 40-19	CRU 35-37
WEZ	63 -	60 -	37 -		S -	SF² -	C -	P -	LxxxD56	580 / 11	PS 40-19	CRU 60-37
WEZ	63 -	60 -	37 -	K	S -	SF² -	C -	P -	LxxxD57	600 / 11	PS 40-19	CRU 60-37

* rotary shutter possible on same flange

** PBN standard, other materials on request

*** specify UHV length L with order

¹ alternatively CL

² alternatively CL, HL or DF

Note: max. Power/Current and Power supply are dependent on filament operating mode (SF, HL, Cl or DF)

Product code:
e.g. 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.