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MOS Capacitance Model

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Click the following links to view model equations for the MOS capacitance model:

• Modified Meyer Model
• Yang-Chatterjee Model
• BSIM Charge Model with 0/100 Partitioning (xpart=1)
• BSIM Charge Model with 40/60 Partitioning (xpart=0)
• BSIM Charge Model with 50/50 Partitioning (xpart=0.5)
• Scaling Effects

The Spectre^® circuit simulator has three charge-based MOS capacitance models that you can select with the model parameter capmod:

• The modified Meyer model
  The modified Meyer model is a first-order model with 40/60 channel charge partitioning in the saturation region. This model does not include any short-channel effects.
• The Yang-Chatterjee model
  The Yang-Chatterjee model uses a 0/100 channel charge partitioning method and includes some short-channel effects.
• The BSIM charge model
  The BSIM charge model provides three methods for partitioning. You choose the method you want with the xpart parameter:
  • 40/60 for xpart = 0 (or xpart < 0.5)
    For xpart = 0, the BSIM charge model is similar to the modified Meyer model, but it includes short-channel effects.
  • 50/50 for xpart = 0.5
  • 0/100 for xpart = 1.0 (or xpart > 0.5)
    For xpart = 1, the BSIM charge model is identical to the Yang-Chatterjee model.

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