INFICON IQM-233 Thin Film Deposition Controller PCI-Express Card Operating Manual - Manual (Page 92)

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IQM-233 Operating Manual
cause power output instability with larger D values. Use of the Filter Readings
parameter can help reduce a power output instability (refer to
section 3.3.3.1.2,
General, on page 3-10 ).
Figure 6-2 Determining the D value
6.5.1 Identifying a Fast or Slow Source
Classifying a source as being fast or slow is based on the time it takes for the rate
to change from a change in power (delay). It is straight forward to measure the
delay. Using manual power, establish a rate and allow it to become steady.
Increase the source power a few percent (~5% if possible). Allow the source to
again stabilize. If the delay time is greater than 1 second, the source is
characterized as slow. All other sources are considered fast. In general, electron
beam (e-beam) sources (unless a hearth liner is used), some very small filament
sources, and sputtering sources are considered fast sources. Thermal evaporation
sources are typically considered slow.
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RATE INCREASE
Power
Rate
POWER INCREASE
TIME
Control DT
Dead Time