US Patent 10026736 Semiconductor devices and methods of manufacturing the same

A semiconductor device includes an active fin on a substrate, a gate structure on the active fin, a gate spacer structure on a sidewall of the gate structure, and a source/drain layer on at least a portion of the active fin adjacent the gate spacer structure. The gate spacer structure includes a wet etch stop pattern, an oxygen-containing silicon pattern, and an outgassing prevention pattern sequentially stacked.