US Patent 7858476 Method for fabricating semiconductor device with recess gate

A method for fabricating a semiconductor device includes forming a hard mask pattern over a substrate, forming a first recess in the substrate and a passivation layer on sidewalls of the first recess using the hard mask pattern as an etch barrier, and forming a second recess by etching a bottom portion of the first recess using the passivation layer as an etch barrier, wherein a width of the second recess is greater than that of the first recess.