Chip Manufacturing · Topic 4 of 16
0%
Chip ManufacturingLesson 4 of 16
Oxidation
Growing a high-quality silicon dioxide layer on the wafer.
What you’ll learn
- How thermal oxide is grown
- Why SiO₂ is so useful
- Where oxide is used
Why it matters
Silicon's native oxide is one of the reasons silicon won — it makes excellent insulators and gate dielectrics.
Explanation
Heating silicon in oxygen or steam grows a dense, stable silicon dioxide (SiO₂) film directly from the wafer surface. Thickness is controlled by temperature and time.
SiO₂ serves as gate dielectric, insulation between layers, and a mask against dopants — a remarkably versatile material.
Visual explanation
Key terminology
- Thermal oxidation
- Growing SiO₂ by reacting silicon with oxygen/steam.
- Gate dielectric
- The insulator under a transistor gate.
- High-k dielectric
- A newer gate insulator replacing SiO₂ at small nodes.
Example
Early MOSFET gates used a few nanometres of thermal SiO₂ as the gate dielectric.
Common mistakes
Watch out for:
- Assuming oxide only sits on top — thermal oxidation consumes some underlying silicon.
Real-world application
At advanced nodes, SiO₂ gate dielectrics were replaced by high-k materials to cut leakage.
Explore related concepts
Continue learning
Oxidation
Up next
Deposition
Chip Manufacturing
Adding thin films of conductors, insulators, and semiconductors layer by layer.
Continue learning →