Silicon Wafers

[ZoNiE]

Does anyone here know who buys used test wafers? I have 7,500 200mm wafers, and am pinging the reclaim houses and such, but perhaps someone here is in the solar industry looking for some?

[inetdog]

Just what is a test wafer?

[ZoNiE]

It is basically a bare silicon wafer used in Semiconductor manufacturing to test and qualify equipment after installation and/or maintenance. They are used to test deposit rates, etch rates, and in my case, polish rates of various dielectric thin films and metal films such as Oxide, Tungesten and Copper.

These have residual films on them that can be removed via reclaim and used for monosilicon solar cells.

[inetdog]

It is basically a bare silicon wafer used in Semiconductor manufacturing to test and qualify equipment after installation and/or maintenance. They are used to test deposit rates, etch rates, and in my case, polish rates of various dielectric thin films and metal films such as Oxide, Tungesten and Copper.

These have residual films on them that can be removed via reclaim and used for monosilicon solar cells.

So would a potential user have to be able to deposit an electrode surface on the back and electrode traces on the front to make them useful? And no doping or other really difficult processing is necessary?

[ZoNiE]

So would a potential user have to be able to deposit an electrode surface on the back and electrode traces on the front to make them useful? And no doping or other really difficult processing is necessary?

Yes, presumably. I don't know the details of Solar Cell manufacture, but I do know that some use silicon wafers. I'm hoping to move the whole lot to a manufacturer. There apparently some still using wafers from my industry.

[Mike90250]

Wafers for PV have to be doped. The time/temp is adjusted for each ingot, which will produce hundreds of wafers. Working out the adjustment for 3 wafers would be pretty prohibitive to do the last 2 wafers. And just doing 2 wafers instead of hundreds at a time, is not likely to go well.

[ZoNiE]

We dope the wafers in an ion implanter, in the semi biz. These are probably all undoped. Except the BPSG wafers, which are Boron doped, but in the silicate glass layer.