Semiconductor devices comprising transistors having vertical channel and method of manufacturing the same

A semiconductor device and a manufacturing method thereof are provided to simplify manufacturing processes and to improve a process margin by using a vertical channel transistor. A semiconductor device includes a cell array region, an active pillar, an annular gate, a channel region, a buried bit line, a word line. The cell array region is defined on a semiconductor substrate(100). The cell array region includes a plurality of unit cells repeatedly arranged along first and second directions. Each unit cell has a uniform pitch. The active pillar(110) is vertically prolonged from the substrate within an active region of each unit cell. The annular gate(122) is used for enclosing a sidewall of the active pillar. The channel region is vertically formed along a length direction of the active pillar. The buried bit line(170) is formed under the active pillar in the substrate. The word line is vertically prolonged from the buried bit line to contact electrically an active gate.