QUE 99177 FIB lift out

FIB lift out of CR 3.0 meteorite QUE 99177

The images are captured in a Scanning Electron Microscope, so they are pictures of backscattered electrons, with different contrast showing different chemistry. The surface where I extract a thin little biscuit of science is a piece of a meteorite. The Focused Ion Beam is a beam of big fat Gallium ions that bombard my sample.

First, I build a layer of platinum metal on the surface where I plan to make a sample section. This layer protects the sensitive meteorite sample from the ion beam. The platinum is deposited by cracking huge molecules of gas that is laced with platinum metal. When the molecules crack open, metal splatters down onto the surface directly below. So I can basically draw a shape and have it fill up with platinum.

Next, the holes are excavated using the focused ion beam. The big ions in the beam essentially act as microscopic wrecking balls, wreaking havoc and digging up a hole wherever I point them. So I dig holes on both sides of the sample section I am creating. Then I come in with a really tiny needle and adhere the sample to the needle. Then I free the sample from the meteorite and it zooms off with the needle.

Next, I adhere the sample to a sample grid using more platinum. Then I tilt the sample grid into the ion beam and shave off very tiny amounts of meteorite until it is ultra thin (~80 nanometers is the goal). The point is to create a sample that is so thin that I can transmit a beam of electrons through it in a transmission electron microscope. This allows me to view the atomic structure and chemistry of the meteorite, thus giving me an idea of how and where the meteorite bits formed and under what sorts of conditions.

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[meteorites11111]

Sorry, I accidentally responded under the wrong account name, but the info still stands.

[ephidapoon]

Very cool!

[itsamechelsio]

(2/2) I use the electron beam to create backscattered e- (the are electrons that get knocked off of the host sample) to create the image.

Additionally, I add the platinum by flooding the chamber with an organometallic gas, and then shooting the ion beam into the gas at specific locations. The ions crack the gas molecules apart, effectively splattering the platinum (that used to be in the gas molecule) onto the sample. Hope that helps! Thanks for the questions!

[itsamechelsio]

(1/2) Thanks so much! I was surprised to see anybody comment on this :). Gallium ions are indeed bombarding the surface. The ions are distinct from electrons, instead they are large atoms of gallium (electrons included) that beat on the surface until tiny little chunks of that surface begin to blast away. There is a separate electron beam (scanning) that is also striking the surface, but electrons are too small to do the kind of excavation that the huge gallium ions can do.

[satanfornoreason]

As someone who isn't scientifically trained, but a pretty smart layman scientist, I've gotta say this video is awesome and so is your description. Thank you so much for taking the time to make this available (and to type it up). Made at least one person (myself) very happy.

Question: you say Gallium ions are bombarding the surface. So are the electrons from the gallium ions the input for the microscope (are they the backscattered e- you mention?)? And how are you adding the platinum? Thanks!