|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Specifications | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| STANDARD EFFUSION CELLS GROUP III AND OTHER MEDIUM VAPOR PRESSURE MATERIALS
|
 |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
Average Power consumption for small and large capacity cell | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
This is the most common kind of MBE source. Radiative heat from a filament surrounding the source crucible induces thermal evaporation and produces a flux of source material towards the substrate. Source temperature (and emitted flux) is regulated by means of a feedback loop between the filament’s external power supply and a thermocouple in contact with the source crucible. ADDON INNOVATION: These are general purpose cells, but temperature is not homogeneous within the crucible. Indeed, the temperature can vary strongly (hundreds of degrees) between the bottom and the lip of the crucible ("Cold Lip" effect). Nevertheless, this cell is widely used since it is easily operated and needs only one power unit and PID control system. ADDON has created a new type of single filament oven for standard effusion cells, which decreases the temperature gradient by preferentially heating the top of the crucible and improving the thermal efficiency. Thus spitting and deposition around the top of the crucible are significantly reduced. Recommended Materials: The standard cell is appropriate for low vapor pressure materials (700 to 1200°C). For Aluminum the "Cold Lip" model or the " New hot zone/cold zone Al Source " model created by ADDON, for growths in a nitrogen or ammonia atmosphere are recommended. Compatibility: This cell comes in various models and is fully compatible with existing systems manufactured by Riber, Varian , VG, SVT, EPI, Perkin-Elmer, Anelva and Ulvac. Other versions are available on request: please provide us with details of desired flange size, connecting tube, and in-vacuum length. Thermocouple: The C Type (W/Re5/26%) is provided (except by special request). All ADDON cells use double parallel T/C at each temperature measurement point. T/C’s are spring loaded for a consistent thermal transfer. Power systems and Temperature Controller: ADDON has designed its cells so as to mate with standard MBE system power supplies. A single power/PID control system is needed for Standard, Low Temperature (Hot Lip) and Cold Lip cells and a double channel power/PID control sytem is needed for a Double Zone cell. Most existing power supplies are compatible. ADDON models are recommended if new power units are needed (see specific documentation). NOTES STANDARD CELLS (UNIFORM FILAMENT) Crucible Capacity, quoted below, correspond to a crucible in vertical orientation. a: specify system power supply or ADDON b: specify system connectors or ADDON c: specify home made system or EPI, DCA, EIKO etc... Integrated shutter: An integrated shutter mechanism can be fitted on most of the cells described here. Integrated cooling circuit: If necessary a water cooling circuit can be integrated on most of the cells described here. VG compatible cells integrate the cooling circuit as a standard feature.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| * When needed Integrated Water Cooling can be added as a factory option (W). Please, do not hesitate to contact ADDON if your system is not listed above or if your system is a custom designed one. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||