Let%27s explore the parasitic capacitances associated with MOSFETs in detail:

1. Junction Capacitance (C_j):
- The junction capacitances in a MOSFET mainly arise due to the depletion charge between the source/drain and the substrate.
- Depending on the source/drain voltage, the depletion charge changes.
- Additionally, when the gate potential exceeds the threshold voltage, a channel is created at the surface, leading to the existence of channel-to-substrate depletion capacitance.

2. Overlap Capacitance:
- Another parasitic capacitance in MOSFETs is the gate-to-source or gate-to-drain overlap capacitance.
- It consists of three components:
- Direct overlap: Represents the capacitance due to direct overlap between the gate and the source/drain regions.
- Outer fringe: Arises from the oxide in the overlap region, which is somewhat thicker than the gate oxide due to a reoxidation step.
- Inner fringe: Also contributes to the overall overlap capacitance.

3. Miller Capacitance (C_gd):
- The Miller capacitance, also known as reverse transfer capacitance, couples the drain voltage variations back to the gate.
- It affects switching speed, introduces a plateau in gate voltage during transitions, and contributes to electromagnetic interference (EMI).

4. Body Capacitance:
- The body effect introduces a capacitance between the substrate (body) and the source.
- Changes in substrate voltage modify the threshold voltage, impacting MOSFET behavior.

5. Design Considerations:
- Engineers must account for these parasitic capacitances during circuit design.
- Proper layout techniques can minimize their impact.
- Understanding these capacitances is crucial for optimizing MOSFET performance.

In summary, managing parasitic capacitances ensures efficient and reliable MOSFET operation.

For more detailed information, you can refer to the [source](https://www.electronics-tutorial.net/Analog-CMOS-Design/MOSFET-Parasitics/Parasitic-Capacitances-MOSFETS/) ¹.


(1) Parasitic-Capacitances-MOSFETS| Analog-CMOS-Design - Electronics Tutorial. https://www.electronics-tutorial.net/Analog-CMOS-Design/MOSFET-Parasitics/Parasitic-Capacitances-MOSFETS/.
(2) What are MOSFETs? - MOSFET Parasitic Capacitance and Its Temperature .... https://techweb.rohm.com/product/power-device/si/si-basic/4873/.
(3) Parasitic capacitance - Wikipedia. https://en.wikipedia.org/wiki/Parasitic_capacitance.

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