P‐183: Study of Electrical Probing through Thin‐film Encapsulation Made of Al 2 O 3 Films Deposited by Low Temperature ALD onto Different Metallic Underlayers

A qualitative study of electrical probing through 25 nm thick amorphous Al 2 O 3 barrier layers, made by low temperature ALD, has been developed. It has been found that the effectiveness of probing depends on the metallic layer beneath the oxide barrier. While a 100 nm thick Cr layer does not allow any probing through the oxide, softer metals like Al turn out to be ideal candidates. From a mechanical point‐of‐view, nano‐indentation studies (normal nano‐indentation with a Berkovitch indenter) onto Al 2 O 3 films made onto the different metals reveal that their mechanical properties are different. While Al 2 O 3 onto Cr is very stiff, Al 2 O 3 deposited onto Al is softer, allowing electrical probes to reach the metal underneath.