MCL – Mercury « constant level » Cell
Details
- Field proven technology for over 30 years
- Large mercury capacity
- Refill without breaking growth chamber vacuum
- Constant flux for hours
- Run to run compositional reproducibility
- Easy to use, allows bakeout operation
Presentation
Riber Mercury cell, model MCL allows the growth of thick MCT layers with precise control in composition for Infra-Red devices. MCL source provides a constant mercury level in a conventional cell configuration, connected to a large reservoir. Gravity keeps constant the level of mercury between the cell and the reservoir. A sensor located in the effusion cell allows to adjust the level of Mercury by mean of the reservoir motion. The large difference between the surface area of the Mercury in the cell and in the reservoir, does not require to move the reservoir during the growth.
Growing 10µm of MCT epilayers at 200°C only requires 1mm of mercury level in the cell. With the level sensor, Mercury level is easily returned to its original pre-calibrated level for the start of each new growth.
Precise control of the cell temperature combined to the Mercury level setting enables an excellent flux stability and reproducibility. The cell is also designed to have a rapid thermal response to temperature changes, for rapid flux variations. This feature is especially useful for applications which specifically require graded doping and composition
Working principle
The RIBER constant level Mercury effusion cell consist of two parts:
– The evaporator, located inside the growth chamber.
– A mercury reservoir, external to the growth chamber, mounted on a vertical translation device.
A Mercury circulation system connects the two parts.
It is based on the communicating vessel principle: displace the reservoir on the vertical translation device causes a change of mercury level in the cell.
This system permits to adjust the mercury level in the cell for evaporation, by a vertical external reservoir movement.
During evaporation, when the reservoir is in a fixed position, a level change of 1 mm corresponds:
– to the evaporation of 11.30 cm3 of mercury for MCL 160.
– to the evaporation of 37.30 cm3 of mercury for MCL 190.
Layout
Technical information
| Characteristics | MCL 160 | MCL 190 |
|---|---|---|
| Filament | Flat Ta filament | |
| Mounting flange | CF40 | CF 63 |
| Reservoir capacity | 1100 cc | 3700 cc |
| Reservoir material | Quartz | |
| Pressure operating range | 10-12 – 10-13 | |
| Maximum pressure | 10-3 Torr | |
| Crucible material | Quartz | |
| Typical operating temperature | 80-110°C | |
| Maximum outgassing temperature | 700°C | |
| Temperature stability | 0,2°C | |
| Power supply | One power supply / One PID | |
| Mercury reservoir level adjustment | Manual lift platform | Motorized lift |
Component interfacing
