Semiconductor Devices with Vertical Channel Structures

A method of manufacturing a semiconductor device, comprising:

• alternately forming a plurality of sacrificial layers and a plurality of insulating layers on a substrate, the plurality of sacrificial layers including a first sacrificial layer and a plurality of second sacrificial layers on the first sacrificial layer, the plurality of second sacrificial layers including a material different from that of the first sacrificial layer;
• forming a channel hole through the plurality of sacrificial layers and the plurality of insulating layers to expose a top surface of the substrate;
• forming a channel contact layer filling a bottom of the channel hole;
• forming a channel layer in contact with the channel contact layer on an inner wall of the channel hole;
• removing the first sacrificial layer and forming a first gate electrode at a position where the first sacrificial layer is removed;
• and
• converting the plurality of second sacrificial layers into a plurality of second gate electrodes by a silicidation process.