Variable Magnetron Cathodes- VTECH Series

The Gencoa Variable VTech Magnetron range can vary the level of magnetic unbalance/ balance and hence vary the level of ion bombardment of the growing film. This is very useful in determining the optimum level of bombardment for specific processes.

The unique VTech magnetron allows the variables of magnetic field properties of the source to create the following effects:

Unbalancing: Variable degree of Unbalance to adjust the electron release and hence the level of ion bombardment of the growing film. This is achieved by retracting the central magnetics and moving the outer magnetics forward. Balancing: To reduce the additional energy input to the growing film and substrate and produce low bombardment conditions. Push the central magnetics forward, retract the outer. Field Strength: To vary the magnetic field strength in order to adjust the discharge voltage and current. This is performed by moving both sets of magnetics back at the same time.
	Magnetic Field Shape: To adjust the magnetic field shape and hence the interaction of the plasma with the anode in order to adjust the minimum operating pressure, striking pressure and extinguishing pressure. This is done in the same way as the balancing and unbalancing and can reduce defects in sputtered dielectric films. The VTech sources produce these effects by the manipulation of permanent magnets inside the magnetron head. On circular magnetrons this is achieved by adjusting manual verniers located on the atmosphere side of the vacuum flange. The adjustment can be performed whilst the cathodes are under vacuum. For rectangular  magnetrons the movement is by lead screws with direct digital readout of the magnetic poles position.
The Vtech magnetrons allow instant and simple adjustment over a very wide range of magnetic parameters. This can be performed before the coating run or dynamically during the deposition process to optimise film properties and hence performance. A typical example for porduction coating  is to have high bombardment during formation of the adhesion layer and low bombardment during the bulk film deposition. The main use of VTech magnetrons is in process and film R&D and is a result of the  powerful of means to change the plasma properties and growing conditions at the film surface. This shows the effect of the plasma properties on the film structure and adhesion  and allows rapid development of improved film structures and performance.

Once the correct level of ion bombardment for a process has been found experimentally with a Vtech magnetron, fixed magnetrons can be manufactured for production purposes with optimum degree of balance or unbalance to create the ideal thin film structure.

The additional advantage from a process or coating development point of view is the rapid determination of the optimum plasma and deposition conditions for specific films types. This also allows the operating envelope in terms of process parameters to attain the required films properties can be determined rapidly and gives an idea of the sensitivity of the plasma conditions to coating performance.

The whole range of Gencoa magnetron source can be produced in the VTech form for target width or diameters of 75mm 3" or greater.

Please also refer to Gencoa Simulation Technology of Balanced and Unbalanced on this website.