Helios

The Helios is a machine currently located in the McDonald building. Common names for the device is: ion mill, Helios, ion beam, etc. The main purpose of this device is that you can cut into samples. This can be used for input and output gratings, defining waveguides, or cutting to view feature profiles.

Notes for Helios Cuts:

• It is very important to bring the ion beam into proven control with each sample
  • Make a test cut onto each sample. Something off to the side and out of the way (a small test that resembles the final cut type)
• Align the sample using the ion view, e-beam and ion beams aren't always in perfect alignment.
• Patterning fine features with a large spot size destroys the pattern.
  • Patterns come out more cleanly, but shallow with a smaller spot size. And deeper, but faded with a larger spot size. (See Stephen to discuss likely values)
• Use the largest spot size possible that still allows for definition of features to come through.

Notes 29 June 2015

• The bits of the file used are the only point taken into account by the Helios
  • The Helios will dwell according to the z value chosen. All else is simple where the beam is aimed. As such, a file built to be 100×100 um space will take the same amount of time to write whether the area allocated by the machine is a 10×10 um space, a 100×100 um space, 10×100 um, etc
• Files should be created by spot size, not by field size. This should increase consistency with the depths cut. (note to be taken of beam widths)
• Current files can be adjusted to account for this innacuracy. Current tests include a 1.5 dimensional increase in width, which appears to be leaving a good mark.
  • Z testing is still underway.
• The Helios is far more magic than science in execution. Much like the ESEM, there is a level of intuition involved in using it. As such, training should occur through the usual usage of the machine.