Methods of forming an integrated circuit device are provided. The methods may include forming a gate structure on a substrate, forming a first etch mask on a sidewall of the gate structure, anisotropically etching the substrate using the gate structure and the first etch mask as an etch mask to form a preliminary recess in the substrate, forming a sacrificial layer in the preliminary recess, forming a second etch mask on the first etch mask, etching the sacrificial layer and the substrate beneath the sacrificial layer using the gate structure and the first and second etch masks as an etch mask to form a source/drain recess in the substrate, and forming a source/drain in the source/drain recess. A sidewall of the source/drain recess may be recessed toward the gate structure relative to an outer surface of the second etch mask.