MOSFET fabrication technology | Fabrication of MOS devices

This page on MOSFET fabrication technology covers fabrication steps used in MOS devices such as MOSFET.

SiO₂ layer formation: An SiO₂ layer is constructed to form on surface of the p-type Si-substrate by exposing top surface to the dry oxygen.

n+ layer diffusion: Two n+ layers are diffused into a p-region through two openings by using the photo-resist and UV ray technique.

Photoetching: The centre part Of SiO₂ is removed by masking and photoetching method.

Re-oxidation: The total top surface of the final material is exposed to dry oxygen. Due to this, SiO₂ layer is formed to completely cover the top surface.

Deposition: Phosphorous glass is deposited to cover the surface of SiO₂.

Photoetching: By UV ray photoetching process, two windows are again opened on SiO₂ layer above the n+ diffused regions.

Metallization: Entire Top surface of the device is metalized using Al material.

Masking and etching: By masking and photo-etching; Al metal contacts are retained to diffused gate, drain and source regions. The unwanted metal regions are etched away.

Figure above depicts fabrication process of NMOS type MOSFET.

MOSFET RELATED LINKS

JUGFET vs MOSFET  Difference between NMOS and PMOS devices  Depletion MOSFET vs Enhancement MOSFET  Application Note on MOSFET as Switch and Amplifier 

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