VERTICAL-TYPE MEMORY DEVICE

A vertical-type memory device includes a plurality of gate electrodes stacked on a substrate; and a vertical channel structure penetrating through the plurality of gate electrodes in a first direction, perpendicular to an upper surface of the substrate. The vertical channel structure includes a channel extending in the first direction, a first filling film that partially fills an internal space of the channel, a first liner on at least a portion of an upper surface of the first filling film and an upper internal side wall of the channel extending beyond the first filling film away from the substrate. The first liner includes n-type impurities. The vertical channel structure includes a second filling film on at least a portion of the first liner, and a pad on the second filling film and in contact with the first liner.