Disclosed herein are various methods of forming replacement gate structures with a recessed channel region. In one example, the method includes forming a sacrificial gate structure above a semiconducting substrate, removing the sacrificial gate structure to thereby define an initial gate opening having sidewalls and to expose a surface of the substrate and performing an etching process on the exposed surface of the substrate to define a recessed channel in the substrate. The method includes the additional steps of forming a sidewall spacer within the initial gate opening on the sidewalls of the initial gate opening to thereby define a final gate opening and forming a replacement gate structure in the final gate opening.