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For the next-generation nonvolatile memory material, the most promising candidate is resistive random access memory (RRAM) which is nonvolatile memory with high density, high speed, and low power consumption. Resistive switching (RS) behavior had been reported in various films including transition metal oxides, perovskite, and chalcogenide. For further application, it is still a challenge to fabricate nanostructures of RS material. Micro-fabrication method involves traditional lithography, chemical etching, electron beam direct writing, nano-imprint, and so on. However, the procedure and the cost of these methods are relatively complex and high for semiconductors process. In this chapter, we demonstrate a method for fabricating sub-micro ZrO 2 lattice by using sol-gel method combined with laser interference lithography and micro-analysis with high-resolution transmission electron microscopy (HRTEM). Researchers used all kinds of techniques to investigate the mechanism such as conductive atomic force microscopy, HRTEM, and scanning electrical microscopy. Despite the extensive research, much of the underlying mechanism is still unclear and controversial. This task can be accomplished only with advanced measurement and technique such as in HRTEM, local conductive atomic force microscopy, and so on. HRTEM sample preparation method for array dots is also discussed. In our research, the bipolar RS behavior can be observed successfully in this structure. And HRTEM observation was used to study the interface between the layers. RRAM unit consists of a conductive atomic force microscope tip as an anode, a ZrO 2 lattice dot as RS material, and a copper electrode as a cathode.

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In this paper, a comparison of the interfacial electronic properties between Pt/Ir conductive atomic force microscopy (C-AFM) tip and ZrO 2 organic array was carried out. A uniformed ZrO 2 array was fabricated with a mean diameter of around 1 μm using laser interference lithography. A C-AFM measurement set-up was built up. The I-V curve was directly measured of the organic ZrO 2 array which shows a resistive switching characteristic by C-AFM measurement. The set voltage is 18.0 V and the reset voltage is −5.0 V. After the Pt layer was coated on the ZrO 2 array, the set voltage decreases to 0.8 V and the reset voltage decreases to −2.2 V. This result shows that Pt layer can prevent the potential drop effectively. The electron barrier height between Pt/Ir C-AFM tip and organic ZrO 2 array was enhanced by sputtering Pt layer on the ZrO 2 organic array.