Source Options
Source OptionsTeardrop shutter – TDS1
A manually operated shutter is available for users without this facility on their vacuum chambers. The shutter is of the rotary teardrop type, and is mounted directly on the end of the source. Drive is provided via a miniature rotary feedthrough fixed on the main flange.
Air-drive & Solenoid Shutters
A compressed air-driven actuator is available for the tear drop shutter with electronic position sensors and control valve with manual override facility. An electrically driven solenoid actuator is also available as an option.
Optical monitor – OED200
A viewport with direct line of sight to the plasma is included as standard with all HD series sources. The optical monitor can be attached to this to measure the intensity of light emitted from the plasma and thus gain a measure of the efficiency of dissociation. The ability to measure the integrated intensity of optical emission has been enhanced by the addition of a spectral line filter which allows the intensity of a particular atomic line to be monitored. Switchable gain levels mean that both integrated and single atomic line intensities can be measured.
Differential Pumping
Our HD20,25 & 60 sources can be supplied fitted inside a differentially pumped tube with integral shutter. In this way the atomic flux can be completely shut off to the substrate while the source is still running, allowing for more precise exposure times. Source parameters may also be set up and stabilised prior to exposure without moving the substrate.
Automation Options
Autotune unit – ATM200
Atom sources are fitted as standard with manual tune units which need adjustment when the plasma is ignited and subsequently if the operating conditions such as power and gas flow are changed. If the source is to be mounted in locations where access is restricted, or if full automation of the system is required, we recommend the autotune option. This makes tuning of the source completely transparent to the user. It is capable of tuning all plasma conditions before, during and after plasma ignition, and will continuously readjust during operation of the source to compensate for changes in the vacuum environment, such as temperature and pressure.
Plasma controller – PCR100
Changes in both gas flow and RF power applied to the Oxford Applied Research range of atom sources, produce an approximately linear response in the plasma brightness which has been shown to correspond to doping density and growth rate. It is therefore possible, by controlling plasma brightness, to control the atomic flux in the same way as temperature is used to control the flux from K-Cells. A control signal is generated from the optical monitor output (described above) and used to adjust the RF power to achieve complete stability of the plasma.
The controller provides long term stability of the source against thermal, pressure and other changes in the chamber and offers a useful safety feature that in the event of plasma failure, RF power to the source is automatically switched off. The RF power supply can be remotely adjusted using the PCR100 which can be switched at will between manual and automatic control.
Piezoelectric gas doser – PLV1000
The PLV1000 piezoelectric gas doser is available for remote control of the gas leak rate to the source. Please click here for more information.
