Reactive deposition getter pumping

The getter pump is a capture-type pump that functions by having a sixrface that chemically reacts with the gases to be pumped or will absorb the gases into the bulk of the getter material. The reactive surface can be formed by continuous or periodic deposition of a reactive material such as titanium or zirconium or can be in the form of a permanent solid surface that can be regenerated. These types of pump are typically used in ultraclean vacuum... 

Mass flow controllers are often used to mix gases either outside or within the deposition chamber. Again, the getter pumping action in the chamber prevents the MFM from giving a correct indication of the reactive gas availability in the chamber, and some type of in-chamber monitoring technique is desirable (Sec. 7.8.3). Mass flow controllers should be calibrated periodically,... 

When depositing reactive materials, the walls, fixturing, and shields in the deposition system can be arranged so as to provide getter pumping by the excess deposited film material. 

Fig. 5.6. Reactive sputter process for depositing the compound film AB. (a) Balance of reactive gas flow Qtot, which is partially gettered at the target (Qt) and at the substrate (Qc) and partially pumped by the vacuum pump (Qp). The fraction of the target surface At that is covered by the compound AB is 6>t. The fraction of the collecting area Ac covered is Gc. j is the sputter current density, (b) Definition of particle fluxes that alter the target and collecting area coverage fractions 6>t and 6>c (see text), (modified from [70])...

Pumping speed in the vacuum chamber can be controlled by throttling the high vacuum valve or by the use of variable orifice conductance valves, which may be servo, controlled by a pressure gauge. A cryocondensation panel to pump water vapor or a sublimation pump (or getter sputter configuration) to pump reactive gases may be used in the deposition... 

Vacuum pump, ion pump A capture-type vacuum pump where a getter material is deposited by sputtering and gaseous ions are accelerated to the reactive surface to react with the surface or be physically buried in the depositing material. Also called a Getter ion pump. 

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