blank run in which nothing or something that will be non-reactive with the sample is

heated in the chamber. Another way to reduce contamination would be to run the

evaporator at the lowest pressure feasible within time constraints and instrument

capability.


Vacuum
Chamber

Electron Beam-.
Source


Metal Source -


Wafer (camped
onto holder)

Shutter


Figure 13. Metal evaporator with electron beam heating source. The wafer is clamped
onto the wafer holder. A shutter blocks the wafer from the metal source until ready for
metal deposition. The electron beam heats the metal source such that the metal begins to
evaporate. The shutter is then opened allowing the evaporated metal to redeposit onto the
wafer.


Figure 14. Optical microscope image of the gold star array on GaAs wafer. Each star is
approximately 10 microns tip to tip with 100 microns between each star.