focused ion beam with more than one type of ion

[Jamie M]

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

 

[Phil Hobbs]

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

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

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510 USA
+1 845 480 2058

hobbs at electrooptical dot net
http://electrooptical.net

 

[Jamie M]

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.

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

http://en.wikipedia.org/wiki/Physical_vapor_deposition
http://en.wikipedia.org/wiki/Ion_plating

cheers,
Jamie

 

[Jamie M]

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

http://en.wikipedia.org/wiki/Physical_vapor_deposition
http://en.wikipedia.org/wiki/Ion_plating

cheers,
Jamie

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