Forum › Category: Layout › Can someone explain the device structure and fabrication process of a FinFET?
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AvatarVLSI Master asked 5 months ago
I think the FinFET structure is pretty unique. The channel is formed on the vertical surface of the silicon fin, and the current flows parallel to the wafer surface. You can see how it makes the device quasi-planar because the source/drain and gate are thicker than the fin itself.
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Avatarsemiconductor answered 5 months ago

In my opinion, the fabrication process seems quite detailed. First, a SOI wafer is used as the starting material. Then, a stack layer of CVD Si N and SiO is deposited on the silicon film to create a hard mask. Electron beam lithography patterns the fine Si-fin.

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AvatarDigitalWorld answered 5 months ago

I've read about this too. The thin silicon fin is the core of the FinFET, acting as the body of the MOSFET. A heavily doped poly-Si film wraps around the fin, making electrical contact with its vertical faces. You know, this helps in reducing the source/drain series resistance.

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AvatarTechGuru answered 5 months ago

I agree with you. The process involves several steps, including etching the SOI layer to expose the silicon only on the sides of the fin. The in-situ phosphorus-doped amorphous silicon is then deposited to form the source/drain pads. You can see the attention to detail in these steps.

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AvatarCodeBook answered 5 months ago

For me, the interesting part is the use of different materials like SiGe for the gate, which improves compatibility with the poly-Si gate process. Also, the self-aligned double gates help in reducing parasitic capacitance and resistance. It’s fascinating how precise the measurements have to be, especially with such tiny dimensions.