MOS transistors and methods of manufacturing the same

摘要

MOS transistors having a low junction capacitance between their halo regions and their source/drain extension regions and methods for manufacturing the same are disclosed. A disclosed MOS transistor includes: a semiconductor substrate of a first conductivity type; a gate insulating layer pattern and a gate on an active region of the substrate; spacers on side walls of the gate; source/drain extension regions of a second conductivity type within the substrate on opposite sides of the gate, the source/drain extension regions having a graded junction structure; halo impurity regions of the first conductivity type within the substrate under opposite edges of the gate adjacent respective ones of the source/drain extension regions; and source/drain regions of the second conductivity type within the substrate on opposite sides of the spacer.