As the demand for data storage and processing continues to rise exponentially, the development of phase change memory (PCM) has gained significant attention. In particular, three-dimensional (3D) vertical cross-point (VXP) array architecture is one of the most promising solutions for PCM fabrication, offering increased integration density and cost-effectiveness compared to the conventional planar memory structures, realized by atomic layer deposition (ALD) due to its excellent controllability and conformality.1) However, the implementation of a 3D VXP structure necessitates selectors, such as an ovonic threshold switch (OTS), to suppress sneak current from unselected cells. The switching behavior of the OTS selector depends heavily on electrode materials, constituting an essential part of the OTS device.2) Thus, detailed engineering of electrode material is required to obtain desirable properties for 3D VXP. Electrodes for 3D VXP require moderate resistivity because of the trade-off between thermal efficiency and power consumption. Moreover, the resistivity of film can be shifted by carbon incorporation. In this regard, we controlled the resistivity of the electrode with varying carbon concentration of the film utilizing ALD technique. In this study, we focus on the development of thermal ALD tungsten carbonitride electrodes for 3D VXP arrays. Tungsten nitride is mainly used as an electrode due to its high thermal stability and conductivity. We present a novel ALD process with intentional carbon control of tungsten nitride to change film properties, including resistivity, by adjusting process parameters. Through systematic control of ALD process parameters, we investigated the impact of carbon concentrations on film characteristics and subsequently analyzed how these variations influence the electrical properties of OTS devices. This research opens the possibility of tuning electrode characteristics in detail, ultimately enhancing the overall electrical performance of the next-generation cross-point memory devices.
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