I am planning to use the diamond themselves as sample container (to avoid flaws related to noble metal use) for a Hydrothermal Diamond Anvil Cell.
To do so, I need to have a square 300x300 microns and 50 microns deep recess milled on the culet of one of the anvils. FIB is the only technique which can produce a virtually perfect shape, which is paramount for my experiments (I tried laser milling but it does not work). I also need to FIB-cut glass wafers 200x200x40 microns dimensions out of glass chips (roughly 1x1x1 mm size, but could be made bigger, if necessary).
At these immense sizes of volume to be milled I would recommend a Xe-plasma FIB. They mill 50 times faster than a gallium FIB and are typically equipped with an electron flood gun for charge compensation which will help you in etching glass.
The Tescan FERA & XEIA microscopes are Xe-FIBs, but I don't know where you could order such service. Maybe contacting Tescan directly will help you, they have a nice application department.
Dear Björn, you are quite right. These are immense volumes for FIB, and that's why this technique is not widely used. Employing diamond as a sample container for T > 1000 °C and P ~ 1 GPa, with aggressive fluids (pH < 1-2, or pH > 10-11) is just so much better than Pt, Au, Pd, etc., but it's expensive (impermeable to H, and C, almost completely unreactive, etc.). I am going to need a grant just for the FIB, I suspect.
Hi,
Your application is not trivial for FIB milling. The cubic volume you ask is huge for FIB, 4.5 million cubic micrometers. I am sitting at a gallium FIB, and for silicon an estimate by the software would be 128 hours at the maximum current of 65 nA, and you typically do not want to use that high probe currents for milling anything fine (no one wants to do a 128 hour mill job). For normal FIB work, making TEM specimens etc. the volume that needs to be removed is several orders of magnitude smaller.
Also, if the sample is polycrystalline, and one must mill directly into a solid specimen, a "perfect" shape is a lot to ask indeed. Some people have been shaping diamond microtools, gives you some idea what has been done with diamond (check for example Precision Engineering 27 (2003) 59-69).
The new Plasma FIBs with Xe ions might be able to do part of the job so you could as around for people with those (they might be able to do at least the volume removal in, say 4-5 hours?) but again, a mathematically perfect shape is very difficult to do, especially as a vertical walled recess into a solid. So, not really an answer to the question, but hope this helps.
Hello,
The dimensions you are interested in are huge for FIB, I tried fib milling of glass micropipettes (for a few microns) and it was taking considerable amount of time. Is there any chance to use laser (or other etching processes) for removing bulk of material and then shape it with FIB?
Additionally to huge time of exposure I would add one more disappointing argument charging will be also enormous preventing milling of desirable shape, so I would search another method like plasma etching selectively aggressive to carbon
There is one other technique to try: laser microjet like that available on Synova's microjet system. It certainly would be much faster than using FIB.
we routinely machine structures of these dimensions in diamond using laser micromachining - we have vast experience with working with diamond! Are you still interested to do this or did you solve the problem
Dear Julie, I am very much still interested. I got some quotes from Oxford Laser, which I have used for a proposal to Royal Society. I should know the outcomes in November. If the proposal is approved, I will have to look up for 'competitive' quotes. I will certainly contact you again then.
Hi Giulio
We have two OI systems for cutting diamond and have been doing this for at least three years, one of my students also spent time with OI - we have an extensive programme ongoing at the moment on diamond and machining is essential to what I need to do - if you need us to do some for you let me know - we also currently run out of Warwick a CDT in Diamond Science and Technology - cheers, Julie - if you want to discuss anything further please email me at [email protected]
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