Valved Phosphorus Cracker Source VPCS

DN63CF ( O.D. 4.5" ) mounting flange compatible with all MBE systems
Thermal cracking up to 1200°C
500 cm³ reservoir
Excellent thermal isolation between low temperature reservoir and hot cracking zone
Cracking stage with integrated water cooling which is used to crack chemical volatile P4 molecules and guarantees safer pressure of the source

Introduction

The main purpose of the VPCS is the controlled evaporation of phosphorus from a reservoir inside the source within a vacuum chamber under high to ultra-high vacuum conditions. The source provides a precise phosphorus flux control by the integrated all metal valve in combination with an easy installation and refilling procedure. The integrated cracking module on top of the injector tube allows conversion of naturally sublimated phosphorus into smaller molecules for improved growth conditions.

The VPCS comprises the following building blocks:

Injector with a cracking stage which allows cracking of P4 molecules and guarantees safer pression of the source
The red phosphorus reservoir with flange for loading of the red phosphorus with the dedicated air-sided heater assembly
The white phosphorus reservoir with air-sided heater
The UHV tight valve unit with embedded heating
Secondary UHV valve for differential pumping of the source

Application

A source concept like this is mainly used for growth of III-V compound materials (GaP, InP etc.). The source is designed exclusively to be operated with red phosphorous.

Technical Data

General
Mounting flange	DN63CF ( O.D. 4.5" )
In-vacuum length L	270 mm
Maximum airside length OL	580 mm
In vacuum outer diameter D	57 mm
Maximum airside radius AR	360 mm
Bakeout temperature (May be lower because of temperature limits of equipment, e.g., cables.)	200°C
Typical cooling water flow rate	30 l/h - 45 l/h
Weight	30 kg
Maximum operational chamber pressure	1 x 10^-5 mbar
P-red reservoir
Temperature sensor	Pt100 class A
Operating temperature	250-400°C
Outgassing temperature	450°C
Crucible capacity	500cc
P-white reservoir
Temperature sensor	Pt100 class A
Operating temperature	60°C
Outgassing temperature	300°C
Crucible capacity	50cc
Cooling	Integrated water cooling shroud
Cracker
Thermocouple	W5%Re/W26%/Re (type C)
Operating temperature	900°C
Outgassing temperature	Up to 1200°C
Cooling	Integrated water cooling shroud

Dimensions

schematic drawing VPCS — Schematic drawing of a Valved Phosphorus Cracker Source VPCS

Specific data

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

Product	CF flange	Nominal capacity	UHV dimensions*** [mm]		max. electrical [W]/[A]	Power supply product code
		[cm³]	[mm]		[W]/[A]	Product code
VPCS	63 -	500 -	L360D34		P-red reservoir 150/3 P-white reservoir 500/8 Valve 150/3 Cracker 300/12	PS 60-3.5 PS 60-14 PS 60-3.5 PS 60-14