INTEGRATED CIRCUIT DEVICES WITH HIGHLY INTEGRATED MEMORY AND PERIPHERAL CIRCUITS THEREIN

An integrated circuit device includes a vertical stack of nonvolatile memory cells on a substrate, which are configured as a vertical NAND string of memory cells. This vertical stack of nonvolatile memory cells includes a plurality of gate patterns, which are spaced apart from each other by corresponding electrically insulating layers. A dummy mold structure is also provided on the substrate. The dummy mold structure includes a vertical stack of sacrificial layers, which are spaced apart from each other by corresponding electrically insulating layers. An insulation pattern is provided, which fills a dish-shaped recess in a first one of the sacrificial layers in the vertical stack of sacrificial layers. This insulation pattern has an upper surface that is coplanar with an upper surface of the first one of the sacrificial layers.