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Aren't there groups out there doing one-off chips using ion implantation? One could envisage a machine that takes a silicon blank and blasts it with a steerabl

by femto 14y ago

Aren't there groups out there doing one-off chips using ion implantation? One could envisage a machine that takes a silicon blank and blasts it with a steerable beam of dopant ions, similar to a small scale Cathode Ray Tube, with the silicon in place of the phosphor. A CRT is feasible to DIY [1,2]. What about an ion implantation device? Okay, it won't do 14nm features first up, but could it make a working transistor?? [1] http://www.instructables.com/id/DIY-Electron-Accelerator-A-Cathode-Ray-Tube-in-a-/ http://www.instructables.com/id/DIY-Electron-Accelerator-A-C... [2] http://www.sparkbangbuzz.com/crt/crt6.htm http://www.sparkbangbuzz.com/crt/crt6.htm

cinquemb 14y ago
maybe one can apply a magnetic field to the surface of the silicon blanks to help with placement of the dopants?
- femto 14y ago
  I can't get a picture of that in my mind. Any more details? One advantage over a CRT is that there is no need to view the "screen", so equipment can go under the Si target. Maybe a very sharp probe, meaning it has a very high electric field intensity at its tip? The probe could be shifted x-y using piezo actuators. If the ion source has a very small physical extent, there would be essentially a "single"[1] electric field line running from the ion source, though the target, to the under-target probe. (Does Si allow E field lines though like this?) The emitted ion would follow the electric field line, crashing into the Si target before reaching the sharp probe. Moving the probe would scan the electric field line, and the point of impact across the surface of the wafer. Alternatively, keep the ion source and probe stationary and move the wafer x-y. [1] small meaning that the spread of the field lines is less than the desired feature size.
  - cinquemb 14y ago
    I'm not sure Si would allow E field lines like that unless it was already doped to a certain extent (at least without diving into matsci book :P). But i was thinking along the same lines by maybe instead of the probe moving, one would move the wafer from one end to another and using an applied magnetic field lines to accelerate ions to the wafer as it moved. What i'm picturing in my head right now is you have two metal coiled cylinders (inner and outer) with the space in between is where the wafer will move through. Now if i could only think of where the ions can be fired in order to follow the magnetic field lines inside between the cylinders to surface of the wafer (theres probably a better setup, but trying to figure out the direction of B and E fields to be able to do something like that in my head is too much for me atm). I think what i'm getting at though is that it might be easier to get nm distances by moving the wafer through B field lines in x direction than moving an E field line x and y.
kanzure 14y ago
> Aren't there groups out there doing one-off chips using ion implantation? Also this group, https://code.google.com/p/homecmos https://code.google.com/p/homecmos

by femto 14y ago

cinquemb 14y ago

maybe one can apply a magnetic field to the surface of the silicon blanks to help with placement of the dopants?

femto 14y ago
I can't get a picture of that in my mind. Any more details? One advantage over a CRT is that there is no need to view the "screen", so equipment can go under the Si target. Maybe a very sharp probe, meaning it has a very high electric field intensity at its tip? The probe could be shifted x-y using piezo actuators. If the ion source has a very small physical extent, there would be essentially a "single"[1] electric field line running from the ion source, though the target, to the under-target probe. (Does Si allow E field lines though like this?) The emitted ion would follow the electric field line, crashing into the Si target before reaching the sharp probe. Moving the probe would scan the electric field line, and the point of impact across the surface of the wafer. Alternatively, keep the ion source and probe stationary and move the wafer x-y. [1] small meaning that the spread of the field lines is less than the desired feature size.
- cinquemb 14y ago
  I'm not sure Si would allow E field lines like that unless it was already doped to a certain extent (at least without diving into matsci book :P). But i was thinking along the same lines by maybe instead of the probe moving, one would move the wafer from one end to another and using an applied magnetic field lines to accelerate ions to the wafer as it moved. What i'm picturing in my head right now is you have two metal coiled cylinders (inner and outer) with the space in between is where the wafer will move through. Now if i could only think of where the ions can be fired in order to follow the magnetic field lines inside between the cylinders to surface of the wafer (theres probably a better setup, but trying to figure out the direction of B and E fields to be able to do something like that in my head is too much for me atm). I think what i'm getting at though is that it might be easier to get nm distances by moving the wafer through B field lines in x direction than moving an E field line x and y.

kanzure 14y ago

> Aren't there groups out there doing one-off chips using ion implantation? Also this group, https://code.google.com/p/homecmos https://code.google.com/p/homecmos