Semiconductor memory device and method of fabricating the same
First Claim
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1. A method of fabricating a semiconductor memory device, comprising:
- etching a substrate wherein a trench is formed that crosses active regions of the substrate;
forming a gate insulating layer on bottom and side surfaces of the trench;
forming a first gate electrode on the gate insulating layer that fills a lower portion of the trench;
oxidizing a top surface of the first gate electrode wherein a preliminary barrier layer is formed;
nitrifying the preliminary barrier layer wherein a barrier layer is formed; and
forming a second gate electrode on the barrier layer that fills an upper portion of the trench.
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Abstract
A method of fabricating a semiconductor memory device includes etching a substrate that forms a trench that crosses active regions of the substrate, forming a gate insulating layer on bottom and side surfaces of the trench, forming a first gate electrode on the gate insulating layer that fills a lower portion of the trench, oxidizing a top surface of the first gate electrode where a preliminary barrier layer is formed, nitrifying the preliminary barrier layer where a barrier layer is formed, and forming a second gate electrode on the barrier layer that fills an upper portion of the trench.
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Citations
20 Claims
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1. A method of fabricating a semiconductor memory device, comprising:
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etching a substrate wherein a trench is formed that crosses active regions of the substrate; forming a gate insulating layer on bottom and side surfaces of the trench; forming a first gate electrode on the gate insulating layer that fills a lower portion of the trench; oxidizing a top surface of the first gate electrode wherein a preliminary barrier layer is formed; nitrifying the preliminary barrier layer wherein a barrier layer is formed; and forming a second gate electrode on the barrier layer that fills an upper portion of the trench. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A semiconductor memory device, comprising:
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a semiconductor substrate that includes a trench; a gate insulating layer disposed in the trench that covers bottom and inner side surfaces of the trench; a first gate electrode disposed in a lower portion of the trench, the first gate electrode including a first metal; a second gate electrode disposed in the trench and on the first gate electrode; and a barrier layer disposed between the first and second gate electrodes, the barrier layer including an oxynitride of the first metal, wherein the second gate electrode has a work-function that is less than the work-function of the first gate electrode. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A semiconductor memory device, comprising:
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a substrate that includes active regions surrounded by a device isolation layer, the active regions extending in a first direction; gate lines buried in trenches formed in an upper portion of the substrate, wherein the gate lines cross the active regions in a second direction that crosses the first direction and divide the active regions into first and second doped regions; and a bit line disposed on the gate lines that extends in a third direction that crosses both of the first and second directions, wherein each of the gate lines comprises; a first gate electrode disposed in a lower portion of the trench, wherein a top surface of the first gate electrode includes oxygen and nitrogen atoms; and a second gate electrode disposed on the first gate electrode.
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Specification