Why do we need SiO2 on a Silicon substrate for Micromachined microstrip antenna?

[ihamieh]

Hey guys,

i'm not sure why do we need SiO2 on a Silicon substrate for Micromachined microstrip antenna? I've designed a rectangular array antenna on a silicon substrate with air cavity, but what I've seen on multiple papers that they use a thin layer of SiO2 on top of the Si substrate for some reason. Does anyone knows?

I appreciate the help

Thanks,
Sam

 

[yadavvlsi]

Array antenna with air gap cavity is difficult to fabricate. Suspended structure may break during etching process due to its own weight.

 

[ihamieh]

Hello Yadavvlsi

So, we will have to remove the silicon dioxide (SiO2) after depositing the patch? The only think that confuses me is that I'm not sure why most of the paper used SiO2 on a silicon substrate without using this layer in calculation ( patch and inset fed dimensions)!

Please advice,

 

[yadavvlsi]

People don't gives all the information in the research papers. They somehow calculate the thickness but don't give it in research paper. Either they use simulation to get it or some hit and trial (by changing SiO2 thickness in fabrication itself). If they gives all the data in paper, anyone can replicate their work.

 

[ihamieh]

hello Yadavvlsi,

Do you think we can omit the SiO2 from the fabrication process if we have enough thickness of Si underneath the patch? I'm thinking of 250um thickness of Si under the patch and 250um of air cavity!

Please advice,
Thanks,
Sam

People don't gives all the information in the research papers. They somehow calculate the thickness but don't give it in research paper. Either they use simulation to get it or some hit and trial (by changing SiO2 thickness in fabrication itself). If they gives all the data in paper, anyone can replicate their work.

 

[yadavvlsi]

Are you a research scholar? Which tool you are using for designing? Can you post a screen shot of your design.? Is there any specific reason for using air cavity not SiO2?