skywater-pdk/docs/rules/device-details/cap_mim/index.rst

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MiM capacitors
--------------
Spice Model Information
~~~~~~~~~~~~~~~~~~~~~~~
- Cell Name: :cell:`sky130_fd_pr__cap_mim_m3__base`, :cell:`sky130_fd_pr__cap_mim_m4__base`
- Model Names: :model:`sky130_fd_pr__model__cap_mim`, :model:`sky130_fd_pr__cap_mim_m4`
Operating Voltages where SPICE models are valid
- :math:`|V_{c0} V_{c1}| = 0` to 5.0V
Details
~~~~~~~
The MiM capacitor is constructed using a thin dielectric over metal, followed by a thin conductor layer on top of the dielectric. There are two possible constructions:
- CAPM over Metal-3
- CAP2M over Metal-4
The constructions are identical, and the capacitors may be stacked to maximize total capacitance.
Electrical specs are listed below:
.. include:: cap_mim-table0.rst
The symbol for the MiM capacitor is shown below. Note that the cap model is a sub-circuit which accounts for the parasitic contact resistance and the parasitic capacitance from the bottom plate to substrate.
|symbol-cap_mim|
Cell name
M \* W \* L
Calc capacitance
The cross-section of the “stacked” MiM capacitor is shown below:
|cross-section-cap_mim|
.. |symbol-cap_mim| image:: symbol-cap_mim.svg
.. |cross-section-cap_mim| image:: cross-section-cap_mim.svg