SEMICONDUCTOR DEVICE HAVING DUAL WORK FUNCTION GATE STRUCTURE, METHOD FOR FABRICATING THE SAME, MEMORY CELL HAVING THE SAME, AND ELECTRONIC DEVICE HAVING THE SAME
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Abstract
A semiconductor device includes a body including a first junction region; a pillar positioned over the body, and including a vertical channel region and a second junction region over the vertical channel region; a gate trench exposing side surfaces of the pillar; a gate dielectric layer covering the gate trench; and a gate electrode embedded in the gate trench, with the gate dielectric layer interposed therebetween. The gate electrode includes a first work function liner overlapping with the vertical channel region, and including an aluminum-containing metal nitride; a second work function liner overlapping with the second junction region, and including a silicon-containing non-metal material; and an air gap positioned between the second work function liner and the second junction region.
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Citations
40 Claims
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1-20. -20. (canceled)
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21. A method for fabricating a semiconductor device, comprising:
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forming a pillar; forming a gate dielectric layer over a lower side surface and over an upper side surface of the pillar; forming a gate electrode including a first work function liner over the lower side surface of the pillar; forming a second work function liner over the upper side surface of the pillar, forming a gap between the second work function liner and the upper side surface of the pillar; capping the gap to form an air gap; and forming a junction region in the pillar to have a depth that overlaps with the air gap and the second work function liner, wherein the air gap is provided between the junction region and the second work function liner. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A method for fabricating a semiconductor device, comprising:
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preparing a substrate which includes a first junction region; etching the substrate to form a first pillar and a second pillar which are separated from each other in a gate trench; forming, in a gate trench, a preliminary gate electrode including (i) preliminary first work function liners over lower side surfaces and upper side surfaces of the first and second pillars, and (ii) second work function liners over the upper side surfaces of the first and second pillars; separating the preliminary gate electrode, and forming a first gate electrode which overlaps with the upper and lower side surfaces of the first pillar and a second gate electrode which overlaps with the upper and lower side of the second pillar; recessing the preliminary first work function liners to non-overlap with the second work function liners, and forming gaps; capping the gaps, and forming air gaps; and forming second junction regions in the first and second pillars to have a depth that overlaps with the air gaps, wherein each of the first and second pillars has first, second, and third side surfaces and the gate trench expose the first side surface of the first and second pillars. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
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Specification