A method of fabricating a semiconductor device, the method including forming on a substrate a transistor that includes a gate electrode and a source and drain region, forming an interlayer insulating film on the transistor, forming a contact hole in the interlayer insulating film to expose a top surface of the source and drain region, and a thin film is formed at an interface between the contact hole and the exposed top surface of the source and drain region. The method further including selectively removing at least a portion of the thin film by performing an etching process in a non-plasma atmosphere, forming an ohmic contact film on the source and drain region where at least a portion of the thin film was selectively removed, and forming a contact plug by filling the contact hole with a conductive material.