focused ion beam with more than one type of ion

Hi,

I was thinking about focused ion beam for deposition/etching/cutting material, I think if there is more than one type of element available, ideally switchable in real time, this could allow for some neat technologies, such as depositing layers of material for different properties (semiconductors etc).. So I don't know if there are systems out there already that can do this with multiple elements, but one idea I had was to use an alloy or homogeneous source for the ions, instead of a pure metal for the ion source, and atomize small amounts off the surface of this with a laser to create ions. Then add a "mass spectrometer" section into the ion accelerator path of the FIB (focused ion beam) setup, and use the mass spectrometer to select which of the elements from the ion source to deposit by changing the deflection coil current in the mass spectrometer.

Another way to make a multi-element focused ion beam could be to have small 1mmx1mmx0.1mm thick plates in a 2D chess board array, each of a different element, and target a laser at the desired element to vaporize a small amount to go into the ion beam. That method could allow easier simultaneous deposition of elements with different masses if there is more than one laser too.

cheers, Jamie

Reply to
Jamie M
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The FIB tools I'm familiar with all use gallium ions. Gallium has a unique set of properties that make it very suitable. It's moderately heavy, with an atomic weight of about 69, and it's a liquid just above room temperature, but has a really low vapour pressure.

Being liquid is important. If you put liquid metal on the tip of a very slightly blunt cone, and apply a large positive bias, the liquid pulls up into an atomically sharp tip, from which you get strong field emission of ions. (The higher you turn up the current, the blunter the tip gets, but at very low current it really is atomically sharp.)

Tip sharpness is a major determinant of resolution.

You can use a FIB to deposit stuff. It's done by putting some nasty organometallic gas into the chamber and decomposing it with the beam where you want the metal deposited. The public FIB we had at Watson could put down platinum, iirc.

It would be tough to put down good quality semiconductor that way--even the Pt lines were pretty ratty.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
Principal Consultant 
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Reply to
Phil Hobbs

Hi,

That type of deposition using gallium to decompose the organometallic gas might not work as well as some type of direct ion deposition such as the focused ion beam. I think a technique similar to that used when painting cars to put opposite charges on the paint and on the car for better paint results could be used with the FIB ion deposition as well.

Also physical vapour deposition techniques and ion plating are useful to build an IDB, ion deposition beam or a FIDB focused ion deposition beam :D

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cheers, Jamie

Reply to
Jamie M

Hi,

A couple more random ideas could be local heating of the part being deposited on via a laser or electron beam, and possibly also de-ionization of the ion beam could be done with the electron beam too which might be useful to help with the adhesion of the ions to the part not sure, but the precision of the electron beam for local heating could be useful anyway.

cheers, Jamie

Reply to
Jamie M

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