US Patent 9997534 Vertical memory devices

A vertical memory device includes a substrate, a channel on the substrate, extending in a vertical direction with respect to a top surface of the substrate, and including a protrusion at a lower portion of the channel, the protrusion extending in a parallel direction with respect to the top surface of the substrate, a semiconductor pattern connecting the protrusion and the substrate, and gate lines stacked and spaced apart from each other in the vertical direction, the gate lines on the protrusion and the semiconductor pattern and surrounding the channel.