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arXiv · 1510.08794

Using atom probe tomography to understand Schottky barrier height pinning at the ZnO:Al / SiO2 / Si interface

R. Jaramillo·Amanda Youssef·Austin Akey·Frank Schoofs·Shriram Ramanathan·Tonio Buonassisi
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Abstract

We use electronic transport and atom probe tomography to study ZnO:Al / SiO2 / Si Schottky junctions on lightly-doped n- and p-type Si. We vary the carrier concentration in the the ZnO:Al films by two orders of magnitude but the Schottky barrier height remains constant, consistent with Fermi level pinning seen in metal / Si junctions. Atom probe tomography shows that Al segregates to the interface, so that the ZnO:Al at the junction is likely to be metallic even when the bulk of the ZnO:Al film is semiconducting. We hypothesize that Fermi level pinning is connected to the insulator-metal transition in doped ZnO, and that controlling this transition may be key to un-pinning the Fermi level in oxide / Si Schottky junctions.

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R. Jaramillo, Amanda Youssef, Austin Akey, Frank Schoofs, Shriram Ramanathan, Tonio Buonassisi. 2015-10-29. Using atom probe tomography to understand Schottky barrier height pinning at the ZnO:Al / SiO2 / Si interface. https://doi.org/10.1103/physrevapplied.6.034016

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