Methods of Forming a Recess Structure and Methods of Manufacturing a Semiconductor Device Having a Recessed-Gate Structure

摘要

Methods of forming a recess structure having a gentle curvature are provided. Such methods include forming a hard mask on a substrate, forming a first preliminary recess on the substrate using the hard mask as an etching mask and forming a spacer on a sidewall of the first preliminary recess. Methods may include forming a second preliminary recess from the first preliminary recess using the spacer as an etching mask and forming the recess structure having an enlarged lower portion from the second preliminary recess using the spacer as an etching mask.