High-purity phosphorus (P2) source
Simple and safe operation with non-inflammable GaP source material
Compatible with most UHV and MBE systems
Various crucibles from 10 to 420 cm³
Precise and fast flux control with high reliability
Optional on-flange integrated cooling shroud and shutter
The Decomposition Source DECO is an ultra-pure source for P2 based on the decomposition of GaP. It is an affordable and easily operated alternative to valved phosphorus sources. Adapted from WEZ and PEZ effusion cells, the simple construction of the DECO with its specially designed Ga-Trapping Cap Unit maintains the advantages of easy installation, full compatibility to all MBE systems, high reliability and low costs of ownership. |
![]() PBN Ga-Trapping Cap on a DECO 40-10-22-KS |
![]() Equilibrium pressures of the components along the metal-rich boundary of the field of solidus of a Ga-P system [R.F.C. Farrow, J.Phys. D, 7, 2436 (1974)] |
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It is also possible to use the DECO as an As2 or Sb2 source. The diagram below shows the analog curves for a Ga-As system. Please inquire for more information.
Equilibrium pressures of the components along the liquidus curve for
a Ga-As system
Typical applications of the DECO are the growth of phosphide compounds (GaInP, InP) in III-V MBE as well as Phosphorus (n-type) doping in Si MBE (with DECO-D, the cell that is explicitly optimized for doping applications). All WEZ standard effusion cells are in principle also available with Ga-Trapping Cap Unit. DECO sources thus combine a most efficient, well-proven heating system with the unique principle of GaP decomposition, which leads to a very stable and reproducible P2 beam formation.
For growth applications the DECO is optimized toward a high flux rates, requiring relatively high operation temperatures and a large orifice of the cap. For these sources a maximum crucible volume is typically chosen to allow extended growth campaigns.
For phosphorus evaporation in large-scale and professional MBE systems, please see the Valved GaP Compound Source VGCS that offers larger capacities and even faster flux control.
Single crystal GaP source material with a purity >6N is offered together with the source.
There are several publications based on phosphorus growth with DECO sources.
Technical data |
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Filament type | Ta wire heating filament |
Thermocouple | W5%Re/W26%Re (type C) (type K on request) |
Operating temperature | 900-1200°C for growth applications |
Outgassing temperature | 1500°C |
Bakeout temperature | 250°C |
Cooling | integrated water cooling or separate cooling shroud |
Crucibles | 10-420 cm³ PBN crucibles |
Options | integrated water cooling (K), integrated rotary shutter (S) |
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Schematic drawing of the GaP Compound Source (drawing shows DECO 40-35-34-S) |
For general information on CF mounting flanges see Flange and Gasket dimensions.
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[cm³] | [mm] | Type | [mm] / [mm] | [W] / [A] | Product code | Product code | ||||||
DECO | 40 - | 10 - | 22 - | S - | C - | P - | LxxxD34 | 120 / 6 | PS 30-10 | PBN 10-22 | ||
DECO | 40 - | 10 - | 22 - | K | S - | C - | P - | LxxxD36 | 120 / 6 | PS 30-10 | PBN 10-22 | |
DECO | 40 - | 35 - | 34 - | S - | C - | P - | LxxxD35 | 180 / 7 | PS 30-10 | PBN 35-34 | ||
DECO | 40 - | 60 - | 37 - | C - | P - | LxxxD38 | 520 / 13 | PS 40-19 | PBN 60-37 | |||
DECO | 63 - | 35 - | 34 - | K | S - | C - | P - | LxxxD60 | 450 / 12 | PS 40-19 | PBN 35-34 | |
DECO | 63 - | 125 - | 54 - | S - | C - | P - | LxxxD55 | 800 / 14 | PS 80-19 | PBN 125-54 | ||
DECO | 63 - | 130 - | 54 - | S - | C - | P - | LxxxD55 | 800 / 14 | PS 80-19 | PBN 130-54 | ||
DECO | 63 - | 200 - | 58 - | C - | P - | LxxxD58 | 1280 / 16 | PS 80-19 | PBN 200-58 | |||
DECO | 100 - | 420 - | 84 - | C - | P - | LxxxD84 | 800 / 12 | PS 80-19 | PBN 420-84 |
* | rotary shutter possible on same flange |
** | PBN standard |
*** | specify UHV length L with order |
Product code:
e.g. DECO 40-10-22-KS-C-L277D36
is a GaP compound source on DN40 CF-flange for a 10cm³ crucible (lip Ø 22), integrated water cooling shroud, shutter, type C thermocouple, in-vacuum length 277mm and diameter.