Adhesion between aluminum and gold layers

[Si14]

Dear all:

I wonder how the adhesion between Al and Au is. I am going to deposit Au on top of Al layer.

Regards.

 

[phyzguy]

The adhesion is not that good. In addition, there is a problem of intermetallic formation (look up "purple plague" on Wikipedia) that can cause problems. For this reason, in my past experience we deposited a Ti or Ti/W layer between the Al and the Au to improve adhesion and prevent intermetallic formation.

 

[Si14]

Great hint. I am going to deposit about 200nm Au on Al layer. So you think it's better to deposit Ti between them? How thick this layer should be? 20nm is fine?

Thank again.

 

[phyzguy]

Yes, I think the Ti layer would be a good idea. 20nm should be thick enough.