The RHEED gun

RHEED guns from S T A I B INSTRUMENTS provide dedicated electron optics systems for diffraction studies, in the range of 10 to 60 keV. By combining electrostatic and magnetic elements, the gun produces a high brightness, small size, and low divergence beam, with extremely low outgassing. The gun mounts completely outside the chamber. The optics are prealigned and need no time consuming adjustment. The system can be serviced onsite and is bakeable. Operation at higher pressure is possible and, if necessary, an efficient differential pumping option is available.

The power supply

The power supply, up to 60 keV, is compact and designed with state of the art electronic components. Gun settings, such as energy, filament current, and beam intensity, are displayed using digital readouts. The power supply is REMOTE CONTROLLED by a compact control box to adjust the beam intensity, focus, and position. The system is equipped with a DIAGNOSTIC capability, which allows a quick and complete test of the RHEED system.

Beam blanking

The electron beam can be turned on and off using this option, keeping the electron load on the sample very low. The blanking signal can also be triggered synchronously with external signals to improve the use of RHEED in the presence of stray magnetic fields or to investigate rotating samples.

Beam rocking

For RHEED analysis, the electron beam must impinge onto the surface at grazing incidence. The unique feature, BEAM ROCKING, allows the precise adjustment and variation of the incidence angle using electronic controls, without moving the sample.

Differential pumping

The standard electron gun is designed to operate at higher pressure, in the 10^-4 Torr range, but the lifetime of the cathode may be reduced. The differential pumping option (TorrRHEED™) allows routine operation at higher pressure and/or with reactive gases. Efficient pumping of the cathode section offers unbeatable versatility.

Computer control

The RHEED system can be entirely computer controlled. The RHEED gun controller includes an Interface Module and a Software Package, and makes use of the RHEED very precise and repeatable. User's parameters can be saved and retrieved, the beam can be turned on and off using the BEAM BLANKING option, and the incidence angle can be adjusted using the BEAM ROCKING feature.

Fluorescent screens

Available in different sizes, the screens are designed to reach high spatial resolution and best contrast. A protective aluminum coating ensures good electric contact, blocks stray light from inside the vacuum chamber, and improves the contrast of RHEED diagrams.

RHEED data acquisition and analysis

RHEED Vision is a powerful data acquisition tool adaptable to every existing RHEED system. Both image processing and real time analysis can be performed. All routines are simply selected through pull-down menus. A large number of data reduction routines are selectable. Additional hardware control modules are available, as for phase locked epitaxy, shutter controls, laser pulse triggering, etc...