Thermal Cracker Cell TCC

Full PBN solution for corrosive materials like Te, Sb, Se, As, Mg
DN40CF ( O.D. 2.75" ) mounting flange c ompatible with all MBE systems
Thermal cracking up to 1300°C
35 cm³ or 130 cm³ PBN crucible
Excellent thermal isolation between low temperature reservoir and hot cracking zone
Integrated water cooling for cracker stage
Integrated rotary shutter Datasheet

Introduction

The Thermal Cracker Cell TCC is an effusion cell equipped with a cracker stage with integrated water cooling shroud on its space-saving DN40CF ( O.D. 2.75") flange. The cell features a crucible size of 35 cm ³ or 130 cm³ which is sufficient for most R&D applications.

The TCC is designed for evaporation of materials at operation temperatures from 100°C to 650°C with an additional cracker stage on the end of the injector tube that provides temperatures up to 1300°C.

The crucible is heated by a tantalum wire heater. The standard crucible material suitable for most evaporants is PBN.

The shielding of the crucible is reduced to optimize the cell for low temperature operation. That way a good flux control for high vapor pressure materials is possible without using an additional valve.

The crucible and cracker zones are shrouded by water cooling therefore the thermal load on the chamber is neglectable.

This is realized by excellent thermal insulation between the low temperature reservoir and the hot cracking zone.

The figure “TCC time-temperature diagramm for heating of the cracker only” shows the temperature response of tube and crucible in case of heating the cracker only. The aim of the TCC is to reduce the thermal crosstalk of the cracker and the reservoir.

The temperature is measured by thermocouples on application critical positions: within the cracker zone, the tube and at the bottom of the crucible.

Even at cracker temperatures around maximum temperature of 1300°C the temperatures of tube and crucible stay unaffected to a large extend.

Application

A source concept like this is used for high vapor pressure materials, which form atom clusters. Typical evaporation elements are As, Se, Sb, Te, Mg.

Technical Characteristics

Mounting Flange	DN40CF (O.D. 2.75")
In‑vacuum dimensions	L=220 mm or 287 mm TL=240 mm or 307 mm (with shutter)
Airside dimensions	AL=405 mm AR=106 mm
Filament	Reservoir: Ta wire filament ,Tube: Ta wire filament, Cracker: Ta wire filament
Thermocouple, Temperature sensor (other types on request)	Reservoir: Type K Tube: Type C Cracker: Type C
Operating pressure	1×10-11 mbar - 1×10-5 mbar
Operating temperature	Reservoir: 100°C – 650°C ,Tube: 200°C – 800°C, Cracker: 300°C – 1200°C
Outgassing temperature	Reservoir: Up to 700°C ,Tube: Up to 850°C, Cracker: Up to 1300°C
Bakeout temperature	200°C
Cooling / water cooling	Reservoir: Integrated water cooling shroud Tube: None Cracker: Integrated water cooling shroud
Cooling water flow	30-90 l/h
Crucibles	PBN 130cm³
Options	integrated rotary shutter (S)
Shutter opening angle	90° ccw
Weight	13 kg
Tube material	PBN
Cracking insert material	PBN