SiC Vertical MOSFET channel length modulation

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In summary, the conversation discussed the difference between lateral and vertical MOSFETs and their respective applications. The main difference is that the drain in a vertical MOSFET is located in a different plane from the source and gate, allowing for stronger voltage withstand capabilities. More information about lateral MOSFETs can be found at the provided link.
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bonkgeek
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Hello , Thank you readind me
I wonder how to represent the reduction in channel length(pinch off seen in lateral MOSFET) for vertical mosfets due to the increase in drain voltage because the drain is at the back, away from the creation of the channel position.
 

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Welcome to PF.

Your diagrams only seem to show lateral MOSFETs. Can you show a typical vertical MOSFET geometry and say where it is used? I have not used them yet.
 
  • #3
Thanks
I am presenting a vertical MOSFET, where the drain is situated in a different plane compared to the source and gate. In this configuration, the current flows vertically from the source to the drain.
This design contrasts with the lateral MOSFET, which you can learn more about by referring to examples available HERE https://www.mks.com/n/mosfet-physics.
Vertical MOSFETs are predominantly used in SiC power MOSFETs, as their vertical structure enables the component to exhibit strong voltage withstand capability.
 

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FAQ: SiC Vertical MOSFET channel length modulation

What is channel length modulation in SiC Vertical MOSFETs?

Channel length modulation in SiC Vertical MOSFETs refers to the variation of the effective channel length due to changes in the drain-source voltage (VDS). As VDS increases, the depletion region at the drain end of the channel widens, effectively shortening the channel length, which can result in an increase in drain current (ID).

How does channel length modulation affect the performance of SiC Vertical MOSFETs?

Channel length modulation affects the performance of SiC Vertical MOSFETs by causing an increase in the drain current (ID) with an increase in drain-source voltage (VDS), even when the gate-source voltage (VGS) is constant. This can lead to a reduction in output resistance and affect the linearity of the device, impacting its performance in analog applications.

Why is channel length modulation more pronounced in shorter channel SiC Vertical MOSFETs?

Channel length modulation is more pronounced in shorter channel SiC Vertical MOSFETs because the relative change in the effective channel length is larger when the physical channel length is smaller. This means that for a given increase in VDS, the percentage reduction in channel length is greater, leading to a more significant impact on the drain current (ID).

How can channel length modulation be minimized in SiC Vertical MOSFETs?

Channel length modulation can be minimized in SiC Vertical MOSFETs by designing the device with a longer channel length, optimizing the doping profile, and using advanced fabrication techniques to control the electric field distribution. Additionally, circuit-level techniques such as using feedback mechanisms can help mitigate the effects of channel length modulation.

What are the implications of channel length modulation for high-power applications of SiC Vertical MOSFETs?

In high-power applications, channel length modulation can affect the stability and efficiency of SiC Vertical MOSFETs. It can lead to variations in output characteristics and reduce the predictability of the device's behavior under different operating conditions. Understanding and mitigating channel length modulation is crucial for ensuring reliable performance in high-power circuits, such as those used in power converters and motor drives.

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