Dynamic random access memories (DRAMs) are currently used as the core memory in computing systems because of their high speed and density. Their demand should continue to grow owing to increased data usage. A unit cell in a DRAM consists of one transistor and one capacitor, and the data are stored in the capacitor. As the size of the unit cell decreases to improve the memory density by aggressive scaling, it is important to secure sufficient capacitance in the capacitor. In this regard, technological advances in the fabrication of capacitors are of great importance; accordingly, the materials and processing of high‐k thin films require developmental innovations. Besides, it is necessary to develop electrode materials that optimize the function of high‐k thin films. In this review, recent advances in achieving sufficient capacitance in DRAM capacitors are summarized from structural and material/process perspectives, and the future direction of DRAM capacitor development is discussed. Atomic layer deposition (ALD) is a key technique that enables the growth of functional thin films for DRAM capacitors; thus, recent advances in the deposition of high‐k and electrode thin films grown using the ALD technique are addressed.

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Metal thin films have been widely used as conductors in semiconductor devices for several decades. However, the resistivity of metal thin films such as Cu and TiN increases substantially (>1000%) as they become thinner (<10 nm) when using high-density integration to improve device performance. In this study, the resistivities of MAX-phase V 2 AlC films grown on sapphire substrates exhibited a significantly weaker dependence on the film thickness than conventional metal films that resulted in a resistivity increase of only 30%, as the V 2 AlC film thickness decreased from approximately 45 to 5 nm. The resistivity was almost identical for film thicknesses of 10−50 nm. The small change in the resistivity of V 2 AlC films with decreasing film thickness originated from the highly ordered crystalline quality and a small electron mean free path (11−13.6 nm). Thus, MAXphase thin films have great potential for advanced metal technology applications to overcome the current scaling limitations of semiconductor devices.

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