Oxygen Resistant Effusion Cell OREZ

Oxygen resistance option available for most wire heater effusion cells
Applicable in oxide MBE systems with chamber pressures up to several mbar
Nickel alloy wire heaters up to 1000°C
Noble metal alloy wire heaters up to 1200°C
Ultimate oxygen resistance by use of platinum shielding
Optional on-flange integrated cooling shroud and shutter

Introduction

Oxygen Resistant Effusion Cells OREZ meet the requirements of oxide MBE and other vaccum applications with high oxygen background pressure. OREZ cells are typically employed in systems with a working pressure from 10 ^-4 to several mbar and can be used up to 1200°C, e.g. for growth of ZnO layers.

Consequent use of selected noble metal and nickel based construction materials render the best possible improvement of common UHV effusion cell models with respect to resistance against oxygen-rich environments.
Special Ni alloy heater wire and shielding parts allow operation in UHV and oxygen-containing atmosphere up to a cell temperature of 1000°C. Operating temperatures of up to 1200°C are attainable by using noble metal alloys for both heater and shieldings.

OREZ 63 with different crucibles — OREZ with dual filament heater, suitable for different crucible shapes with capacities of 60 cm³, 80 cm³ and 125 cm³

Since OREZ cells are essentially modifications of standard wire heater effusion cells, almost the same range of flange and crucible sizes is available as for WEZ and NTEZ effusion cells.
The same also applies to the number of available options. OREZ cells are offered with the full range of filament configurations. Integrated cooling and shutter are possible as required. The OREZ can thus be adapted to almost every vacuum system.

In view of the wide range of applications and evaporants, there is no standard crucible material for the OREZ. The most commonly used materials are PBN, Al₂O₃ , BeO, and iridium. The maximum admissible temperature for PBN however depends on the oxygen pressure level, due to the formation of boron oxide.

Application

A steadily increasing number of applications requires robust, reactive gas resistant equipment for material deposition, often employed in combined UHV and reactive gas process steps carried out in one vacuum system.
OREZ cells are therefore designed to operate in a pressure range from UHV up to nearly atmospheric pressure. Best performance is achieved in a pressure range from 10^-6 to 10^-3 mbar.

Typical applications are the formation of oxide layers by surface oxidation, growth of oxide films by evaporation of metals in oxygen atmosphere, and direct evaporation of oxides. Surface oxide layers and thin films are widely used as insulator materials, e.g. in microelectronic devices. Thick oxide films are often used in sensors and optical devices, due to the multifaceted optical, magnetic, electrical and semiconductive properties of oxides.

Note : For chamber pressures below 10^-6 mbar we recommend using standard UHV effusion cells ( WEZ , NTEZ , etc.). For higher pressures above 10 ^-3 mbar it should be taken into account that due to the very short free path length of the evaporated molecules one leaves the molecular beam regime. In both cases please inquire for more advice.

Technical Data

Filament type	Ni alloy (T_max = 1000°C) or noble metal alloy (T _max = 1200°C) wire heating filament: standard ( SF ), hot lip ( HL ), cold lip ( CL ), dual ( DF )
Thermocouple	NiCr/NiAl (type K)
Operating temperature	200-1200°C (depending on filament material and operation conditions)
Outgassing temperature	1000 / 1200°C (depending on filament material)
Bakeout temperature	250°C
Cooling	integrated water cooling or separate cooling shroud
Crucibles	10-125 cm³; PBN, Al₂O₃ , BeO crucibles (other materials on request)
Options	integrated water cooling ( K ), integrated rotary shutter ( S )

Dimensions

Schematic drawing OREZ — Schematic drawing of the Oxygen Resistant Effusion Cell OREZ (drawing shows OREZ 40-10-22-KS

Specific data

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

Product	CF flange	Nominal capacity	Lip diameter	Cooling	Shutter*	Filament material	Shielding material	Filament type	Thermocouple	Crucible material**	UHV dimensions*** [mm]	max. electrical [W]/[A]	Power supply product code	Crucible product code
		[cm³]	[mm]					Type	Type		[mm] / [mm]	[W] / [A]	Product code	Product code
OREZ	40 -	10 -	22 -		S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD34	120 / 7	PS 30-10	CRU 10-22
OREZ	40 -	10 -	22 -	K	S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD36	120 / 7	PS 30-10	CRU 10-22
OREZ	40 -	35 -	34 -		S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD34	180 / 9	PS 30-10	CRU 35-34
OREZ	40 -	35 -	37 -			Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD37	200 / 10	PS 30-10	CRU 35-37
OREZ	40 -	60 -	37 -			Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD38	240 / 10	PS 30-10	CRU 60-37
OREZ	63 -	35 -	34 -	K	S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD58	180 / 9	PS 30-10	CRU 35-34
OREZ	63 -	35 -	37 -	K	S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD54	200 / 10	PS 30-10	CRU 35-37
OREZ	63 -	60 -	37 -		S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD38	240 / 10	PS 30-10	CRU 60-37
OREZ	63 -	60 -	37 -	K	S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD58	240 / 10	PS 30-10	CRU 60-37
OREZ	63 -	60 -	54 -		S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD55	300 / 10	PS 40-19	CRU 60-54
OREZ	63 -	125 -	54 -		S -	Ni¹ /	Ni² -	SF³ -	K -	P -	LxxxD55	300 / 10	PS 40-19	CRU 125-54

* rotary shutter possible on same flange ¹ Pt alloy wire filament on request ** no standard, inquire for your particular solution ² Pt foil shielding on request *** specify UHV length L with order ³ alternatively CL, HL or DF

Product code: e.g. OREZ 40-10-22-S-Pt/Ni-HL-K-B-L287D34 is an oxygen resistant effusion cell on DN40 CF-flange for a 10cm³ crucible (lip Ø 22mm), integrated rotary shutter, Pt foil shielding, Ni alloy wire hot lip filament, type K thermocouple, BeO crucible, in-vacuum length 287mm and diameter 34mm.