Semiconductor devices having a vertical channel transistor and methods of forming the same

A method of manufacturing a semiconductor device, comprising:

• forming hard mask patterns arranged in a first direction and a second direction crossing the first direction on a substrate;
• forming pillar-shaped source parts arranged in rows in the first direction and columns in the second direction by etching the substrate using the hard mask patterns as masks;
• forming spacers on sidewalls of each of the source parts;
• forming pillar-shaped channel parts extending below each of the source parts by further etching the substrate using the hard mask patterns and the spacers as masks to form active pillars, wherein ones of the active pillars include respective ones of the source parts and the channel parts;
• doping an exposed region of the substrate between the active pillars with a bit line dopant;
• forming device isolation trenches in the substrate proximate the region doped with the bit line dopant to define buried bit lines that extend along the respective columns of the active pillars;
• forming channel dopant regions in the channel parts;
• and
• forming gate electrodes on an outer surface of the channel parts that surround the channel dopant regions.

A semiconductor device comprising:

• a substrate;
• a plurality of active pillars arranged in a matrix on the substrate, wherein each of the pillars includes a channel part that includes a channel dopant region disposed in a surface of the channel part;
• and
• a gate electrode that surrounds an outer surface of the channel part.