Semiconductor device and methods of formation

Abstract

A two-step etch technique is used in a continuous polysilicon on oxide definition edge (CPODE) recess process to form a recess in which the CPODE structure is to be formed. The two-step process includes performing a first etch operation using an isotropic etch technique, in which a recess in a dummy gate structure is formed to a first depth. A second etch operation is performed using anisotropic etch technique to form the recess to a second depth. The use of the anisotropic etch technique results in a highly directional (e.g., vertical) etch of the dummy gate structure in the second etch operation. The highly directional etch provided by the anisotropic etch technique at or near the bottom of the dummy gate structure reduces, minimizes, and/or prevents etching into adjacent portions of an interlayer dielectric (ILD) layer and/or into source/drain region(s) under the portions of the ILD layer.