Morphological instability of Ag films caused by phase transition in the underlying Ta barrier layer
2014 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 105, 071604- p.Article in journal (Refereed) Published
Wide-bandgap (WBG) semiconductor technologies are maturing and may provide increased deviceperformance in many ﬁelds of applications, such as high-temperature electronics. However, thereare still issues regarding the stability and reliability of WBG devices. Of particular importance isthe high-temperature stability of interconnects for electronic systems based on WBG-semiconductors. For metallization without proper encapsulation, morphological degradation canoccur at elevated temperatures. Sandwiching Ag ﬁlms between Ta and/or TaN layers in this studyis found to be electrically and morphologically stabilize the Ag metallization up to 800C, com-pared to 600C for uncapped ﬁlms. However, the barrier layer plays a key role and TaN is found tobe superior to Ta, resulting in the best achieved stability, whereas the difference between Ta andTaN caps is negligible. The b-to-a phase transition in the underlying Ta barrier layer is identiﬁedas the major cause responsible for the morphological instability observed above 600C. It isshown that this phase transition can be avoided using a stacked Ta/TaN barrier.
Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2014. Vol. 105, 071604- p.
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject Engineering Science with specialization in Electronics
IdentifiersURN: urn:nbn:se:uu:diva-230204DOI: 10.1063/1.4893768ISI: 000341189800016OAI: oai:DiVA.org:uu-230204DiVA: diva2:739197
FunderSwedish Research Council, 2010-4460Swedish Foundation for Strategic Research , RE10-0011