AVS 65th International Symposium & Exhibition
    Thin Films Division Thursday Sessions
       Session TF+PS-ThM

Paper TF+PS-ThM11
Resistivity of the Alumina Diffusion Barrier in Catalytic Carbon Nanotube Growth

Thursday, October 25, 2018, 11:20 am, Room 104B

Session: Deposition Processes for 3D and Extreme Geometries
Presenter: Berg Dodson, Brigham Young University
Authors: B.D. Dodson, Brigham Young University
G. Chen, Brigham Young University
R.C. Davis, Brigham Young University
R.R. Vanfleet, Brigham Young University
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By using photolithography techniques and catalytically grown carbon nanotubes (CNTs) it is possible to fabricate high aspect ratio structures that can be used as scaffolds for MEMS devices. The drawback of making CNT structures this way is it is difficult to electrically connect to them since they are grown on an insulating alumina layer. However, previous work demonstrates that the alumina layer becomes conductive during CNT growth. Two-point probe measurements from tungsten to a CNT post in a 100 nm tungsten/alumina 50 nm/CNT stack yielded 580 ± 65 Ω. I present TEM based data showing how this change in conductivity correlates with iron and carbon diffusing into the alumina layer during CNT growth. I will also show how the observed diffusion in these samples compares with what is predicted by diffusion models as well as how the change in resistivity compares to what is expected in doped alumina.