Specific Process Knowledge/Thin film deposition/Deposition of Zinc: Difference between revisions

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 Small Zn pellets (Lesker) were evaporated from an alumina crucible in Source 1 of the Lesker Thermal evaporator onto InP dummy substrates and InGaP substrates.
-It was possible to use an automatic program after some adjustments. A stable deposition rate of 0.5 Å/s was obtained with a max. power of 14.5 % after approx. 15 min of ramping and soaking. The final PID parameters were P 15, I 2 and D 1.
+It was possible to use an automatic program after some adjustments. A stable deposition rate of 0.5 Å/s was obtained with a max. power of 14.5 % after approx. 15 min of ramping and soaking. Depositions at 0.3 Å/s and 1 Å/s were not stable. The final PID parameters were P 15, I 2 and D 1.
 It is important not to use too high power as this will give a very fast increase in the deposition rate once the evaporation is started. For new Zn pellets, an oxide removal run is recommended before the actual deposition. The max power needs to bel slightly adjusted for this run (slightly higher than for already-melted pellets).
 Frequently exchange the QCM crystal (quartz crystal monitor) which is used to measure the thickness of the deposited film. After about 1 micron accumulated deposition, the crystal severely underestimated the thickness, whereas a fresh sensor measured accurately (film thickness verified with Dektak profilometry).