Authors

Zhongkui Tan

Type

Text

Type

Dissertation

Advisor

Likharev, Konstantin K. | James E. Lukens | Ismail Zahed | Andreas Mayr.

Date

2010-05-01

Keywords

Physics, Condensed Matter | crested barrier, electron transport, metal oxide, rapid thermal annealing, reproducibility, resistive bistability

Department

Department of Physics

Language

en_US

Source

This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.

Identifier

http://hdl.handle.net/11401/72694

Publisher

The Graduate School, Stony Brook University: Stony Brook, NY.

Format

application/pdf

Abstract

This work presents results of an experimental study of electron transport through few nanometer-scale metal oxide junctions of two types:First, we have measured transport properties of Nb/Al/Nb junctions fabricated using thermal oxidation or rf-plasma oxidation at various conditions, with rapid thermal post-annealing (RTA) to improve junction endurance in electric fields in excess of 10 MV/cm. The results indicate that such junctions may combine high field endurance (corresponding to at least 10^10 write/erase cycles in floating-gate memories) and high current density (corresponding to 30-ns-scale write/erase time) at high voltages, with very low conductance (corresponding to retention time scale ~0.1 s) at low voltages. We discuss the improvements necessary for the use of such junctions in advanced floating-gate memories.Second, we have studied resistive bistability (memory) effects in junctions based on several metal oxides, with a focus on sample-to-sample reproducibility which is necessary for the practical use of such junctions, in particular as crosspoint devices of hybrid CMOS/nanoelectronic circuits. Few-nm-thick layers of NbOx, CuOx and TiOx have been formed by thermal and plasma oxidation, at various deposition and oxidation conditions, both with or without rapid thermal post-annealing. The resistive bistability effect has been observed for all these materials, with particularly high switching endurance (over 1000 switching cycles) obtained for single-layer TiO2 junctions, and the best reproducibility reached for multi-layer junctions of the same material. Fabrication optimization has allowed us to improve the OFF/ON resistance ratio to about 1000, though the sample-to-sample reproducibility is so far still lower than that required for large scale integration.

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