DigitalWorld asked 3 months ago
I think the channeling effect happens when ions penetrate deeper into the wafer than expected because they move between the spaces in the silicon crystal lattice. To prevent this, I have read that you can tilt the wafer at a small angle during implantation. By doing this, we can stop the ions from entering those channels and make the doping more controlled, but it might cause uneven doping at the edges.
2 Answers
semiconductor answered 3 months ago
From my experience, the channeling effect is when ions follow the regular pattern of the silicon atoms and go too deep. You can stop this by applying a thin oxide layer on the wafer surface. When we use this method, the ions scatter and don't go straight down, which prevents them from channeling. I feel this is a better method because it avoids the asymmetric doping problem.
VLSI Master answered 3 months ago
You might notice that the channeling effect can make doping unpredictable if not managed properly. We usually deal with it by either tilting the wafer or using a thin oxide layer. If you tilt the wafer, it stops the ions from channeling, but be careful—you might get uneven doping near the resist mask edge(We also called it as WPE(Well Proximity Effect). Using a thin oxide layer seems more effective since it scatters the ions, giving us a more uniform doping depth without those risks.
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