Abstract: A semiconductor device comprising a gate electrode on a substrate, a source/drain pattern on the substrate on a side of the gate electrode, and a gate contact plug on the gate electrode are disclosed. The gate contact plug may include a first gate contact segment, and a second gate contact segment that extends in a vertical direction from a top surface of the first gate contact segment. An upper width of the first gate contact segment may be greater than a lower width of the second gate contact segment.

Abstract: An etching gas composition includes a first organofluorine compound having 3 to 6 carbon atoms, and an organosulfur compound having 1 to 4 sulfur atoms. The organosulfur compound may include a carbon-fluorine (C—F) bond, a carbon-sulfur (C—S) bond, at least one carbon-carbon double (—C?C—) bond. When the etching gas composition is used, excellent etch selectivity may be obtained, and the linearity and verticality of a pattern may be greatly increased by improving line edge roughness (LER) and line width roughness (LWR) due to an improvement in the roughness of an etched surface.

Abstract: The present invention relates to a method for forming a silicon-containing thin layer at a low temperature, and in particular, to a method for forming a silicon-containing thin layer by carrying out atomic layer deposition (ALD) at a low temperature.