Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Shared contacted diffusion in layout

  1. May 6, 2014 #1
    I am confused about shared contacted diffusion in CMOS layout.
    Is it possible to use shared contacted diffusion for two nMOS transistors with different widths?
    BTW, two nMOS and pMOS transistors are never shared contacted diffusion, right?
    Last edited: May 6, 2014
  2. jcsd
  3. May 6, 2014 #2


    User Avatar
    Science Advisor

    Yes you can share a diffusion between devices with different widths, that is no problem. One device extends farther than the other. In fact you should share diffusion as much as possible to reduce parasitic capacitance.

    No you can't share diffusions between PMOS and NMOS devices. This is because the diffusions are different doping types! (in other words they are not in the same well). You are correct about that.
  4. May 7, 2014 #3
    Thank you.
    I am learning about analog design. Hope you could help!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Shared contacted diffusion in layout
  1. Chip layout (Replies: 6)

  2. Layout verification (Replies: 2)

  3. PCB layout question (Replies: 16)

  4. Circuit layout (Replies: 22)