Passivization layer on top of Silicon di oxide

Hi,

I have a question on need of a Passivization layer on top of Silicon di oxide while designing a planar spiral inductor in HFSS

Q1 Why it is used?
Q2 How does the Relative permittivity of material affects the design?
Q3. Which is the best practical material to be used?

Thanks
Hemanshu

Passivation layer is mainly used for protection, to protect the underlying circuits buried between oxide layers.

The permittivity of the top passivation is high compared to those of oxide layers. But roughly speaking, it does not influence the inductor performance much.

The material used as passivation layer is determined by foundry. Unless u can access to modify that, forget changing the process.

Thanks for the reply