Semiconductor device

A semiconductor device comprising:

• a substrate;
• a bit line extending in a first direction on the substrate;
• a pair of vertical channel patterns on the bit line;
• a back gate electrode between the pair of vertical channel patterns and extending in a second direction perpendicular to the first direction across the bit line;
• a pair of word lines outside the pair of vertical channel patterns and extending in the second direction;
• and
• contact patterns connected to each of the pair of vertical channel patterns,
• wherein each of the pair of vertical channel patterns is an epitaxially grown layer having a top facet at a topmost portion of an inclined sidewall and a bottom facet at a bottommost portion of an inclined sidewall.

A semiconductor device comprising:

• a substrate;
• a bit line extending in a first direction on the substrate;
• a first vertical channel pattern and a second vertical channel pattern on the bit line;
• a back gate electrode between the first and second vertical channel patterns and extending in a second direction perpendicular to the first direction across the bit line;
• a first word line extending in the second direction from one side of the first vertical channel pattern;
• a second word line extending in the second direction from other side of the second vertical channel pattern;
• a gate insulating pattern conformally between the first and second vertical channel patterns and the first and second word lines and on top surfaces of the first and second word lines;
• a contact pattern connected to each of the first vertical channel pattern and the second vertical channel pattern;
• and
• a data storage pattern connected to the contact pattern,
• wherein, when viewed from a cross-sectional view, each of the first vertical channel pattern and the second vertical channel pattern has a trapezoidal shape that is a mirror image symmetrical structure with respect to the back gate electrode.