Semiconductor device with buried gate and method for fabricating the same

摘要

A method for fabricating a semiconductor device includes forming landing plugs over a substrate, forming a trench by etching the substrate between the landing plugs, forming a buried gate to partially fill the trench, forming a gap-fill layer to gap-fill an upper side of the buried gate, forming protruding portions of the landing plugs, and trimming the protruding portions of the landing plugs.

主权项

1. A semiconductor device comprising:
a substrate having a trench arranged therein; a buried gate partially filling the trench; a first gap-fill layer arranged over the buried gate and protruding from a surface of the substrate; a landing plug having a buried portion arranged over the substrate between the first gap-fill layer and a protruding portion arranged over the buried portion; a second gap-fill layer formed over the first gap-fill layer; and a spacer formed between the first gap-fill layer and the second gap-fill layer and surrounding sidewalls and a bottom surface of the second gap-fill layer, wherein an upper surface of the buried gate is lower than a bottom surface of the landing plug, and wherein the protruding portion of the landing plug has a smaller area than the buried portion of the landing plug.