Startup slices solar panels using ion gun After keeping a low profile for some years, a startup called Twin Creeks Technologies has gone public with an interesting approach to making solar panels: it uses an ion gun to slice ultra-thin leaves from a wafer. Its approach is to fire hydrogen ions at a substrate, a technique the company says produces very thin wafers …
Surely the materials cost is very marginal, and 'cheaper to produce' depends more on a state-of-the-art efficient factory?
Are they suggesting that thinness/flexibility will bring solar panels to altogether new applications? If so, great, but if not they're in a marketplace already suffering overcapacity and fierce competition.
Wafers are normally sawn individually from a crystal boule and then polished.
They aren't cheap, and if you want more of them you have to slice the wafer again finer.
This system gives you a lot of cheap smooth wafers from a single initial one.
Thin flexible wafers have a few other advantages - you can glue them to flexy plastic to make roof coverings rather than having to ix rigid glass-like sheets in current thick panels.
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These are flexible so they can go at surfaces where we cannot stick legacy ones easily - for example on the curved parts of car body panels or 1:1 replacements for existing roof tiles.
The material cost in solar panels is not marginal by the way. It makes up for a considerable part of the panel cost.
"Hmm, when Si was $400 a kg that might have been interesting. At today's price of $35 to $40 (around production cost) I'm not entirely convinced."
While I partly agree, the issue here is not just the saving in wafer slice cost (which is still a very useful reduction) - it is also the substrate mounting thickness and cost (metal), handling yield (theoretically should be better vs thinner conventionally sawn wafers) and the knock potential packaging savings for the finished active area (the PV module, not active area as in CMOS implant).
"Also, wafers are getting down to 80 microns with standard equipment already these days....."
Yes but the waste ratio goes up (the saw thickness isn't going to scale in the same as the effective wafer thickness can), as does the wafer breakage, as the sawn wafer thickness goes down - so even at 80um + (lets be very generous) 120um for sawn wafer versus 30-60um + 20um for hydrogen implant shearing there is the potential for saving.
Are these guys bigging up their claims to help with inward investment ?... of course. Is it interesting tech with potential real-world consequences, not least of which is cost reduction ?... I think so - i'm sure time will tell, but I really do hope they get some cash so they can try and prove it one way or the other.
Sounds a lot like the smart cut process that is currently used by SOItech to make thin SOI wafers.
The ion implant results in stress at the depth the ions end up in the lattice after implantation. The wafer can then be split along the stressed zone to give a thin slice. In the smart cut process you stick wafer A, with a stressed buried slice, to wafer B, which is coated with oxide. Pull, and a slice of wafer A ends up on the (now buried) oxide of wafer B. Silicon on Insultor (SOI).
http://electronicdesign.com/article/embedded/smart-cut-process-technique-mdash-an-overview3400
Because the terms are interchangeable? Admittedly calling them protons is less wordy, but liable to cause confusion to those who aren't aware that nicking the electron from a neutral hydrogen atom leaves you with just a proton.
Maybe the hydrogen ions are acting in a more classical particle-like manner than the wave-like manner that the use of the term proton would imply, or the fact that they are charged particles is relevant, so referring to them as ions rather than protons stresses that fact?
Spend *shed-loads* of cash on hardware, chemicals and energy to make a raw material with PPB impurity levels.
Throw away 1/3 of it in processing.
BTW while much like the Soitec process SOI is viewed as a *premium* price wafer, whereas these have to be base price (is there a "PV" grade price?) or cheaper with low scrap and low cost. That makes this engineering *tricky*.
Note that by starting with monocrystal PV cell material they get to *leverage* any current or future Silicon work, which is still the bulk semiconductor by a *very* wide margin.
However for *really* big, low cost you'd need to skip *any* conventional slicing.
I picture a system under permanent high vacuum with something like a revolver cylinder inside it. The number of boules corresponding to the number of steps in the slicing process.
boules in -> slices out. No waste.
With modern boules being 300mm in diameter (going to 320mm soon) and 10m long it would be a beast of a machine to make but you would get back most of the kerf loss.
Of course this *all* depends on them working out how to *handle* these thin "floppy" wafers to process them into cells.
Thumbs up on trying to make a niche, high precision process into a bulk mass produced one. I hope they success
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