Abstract: A transistor including a semiconductor substrate defined with an active region and a device isolation region, a gate formed on the semiconductor substrate, an insulating spacers formed on respective side walls of the gate, and source/drain junctions formed in the semiconductor substrate at opposite sides of the gate, the source/drain junctions having asymmetrical junction structures, respectively, wherein the gate has a lower portion arranged on the active region of the substrate, the lower gate portion having a stepped profile having a lower surface, an upper surface and a vertically-extending side surface. The invention also provides a method for manufacturing this transistor. In accordance with this transistor structure, an increase in the dopant concentration of a storage node is prevented. Accordingly, a reduction in the amount of leakage current is achieved, so that an improvement in the refresh characteristics of the transistor is achieved.

Abstract: Disclosed is a method for manufacturing a semiconductor device having recess channels and asymmetrical junctions. The method includes forming an impurity region for adjusting the threshold voltage by implanting ions into a bit line junction of a semiconductor substrate, which includes storage nodes junction, the bit line junction, and channel regions between the source and bit line junctions, and portions of the channel regions of the semiconductor substrate adjacent to the bit line junction; forming recess channel trenches by etching the channel regions of the semiconductor substrate to a designated depth; forming a gate stack on the semiconductor substrate provided with the recess channel trenches; and forming the storage nodes junction and the bit line junction on the semiconductor substrate provided with the gate stack via ion implantation.

Abstract: Disclosed are an asymmetric recessed gate MOSFET, and a method for manufacturing the same. The asymmetric recessed gate MOSFET comprises: recess regions formed at a predetermined depth in a semiconductor; recessed gate electrodes formed at a predetermined height on a semiconductor substrate by gap-filling the recess regions, and misaligned with the recess region corresponding to one of the source/drain regions; spacers formed on sides of the recessed gate electrodes; and source/drain regions implanted with a dopant formed in the semiconductor substrate exposed between the spacers. The overlap between the gate electrodes and the source/drain regions can be reduced by having one of the source/drain regions misaligned with the recess regions in the recessed gate structure, and abnormal leakage current caused by consistency between an electron field max point A and a stress max pint B can be sharply reduced by changing the profile of the source/drain regions.

Abstract: Disclosed herein are a recess-gate structure in which junctions have a thickness significantly smaller than the thickness of a device isolation layer to thereby prevent shorting of the junctions located at opposite lateral sides of the device isolation layer close thereto, resulting in an improvement in the operational reliability of a resultant device, and a method for forming the same. The recess-gate structure comprises a silicon substrate in which an active region and a device isolation region are defined, a plurality of gates formed on the substrate, gate spacers formed at the side wall of the respective gates, and junctions formed in the substrate at opposite lateral sides of the gates and defining an asymmetrical structure relative to each other. A gate recess is defined in the active region of the substrate to have a stepped profile consisting of a bottom plane, top plane, and vertical plane.