Semiconductor device including a superlattice and replacement metal gate structure and related methods

A semiconductor device comprising:

• a substrate having a channel recess therein;
• a plurality of spaced apart shallow trench isolation (STI) regions in said substrate;
• source and drain regions spaced apart in the substrate and between a pair of the STI regions;
• a superlattice channel in the channel recess of said substrate and extending between the source and drain regions, the superlattice channel contacting the source and drain regions, the superlattice channel including a plurality of stacked groups of layers, each group of layers of the superlattice channel comprising a plurality of stacked silicon monolayers defining a base silicon portion and at least one oxygen monolayer constrained within a crystal lattice of adjacent base silicon portions;
• and
• a replacement gate comprising a high K dielectric layer over the superlattice channel and a metal gate electrode over the high K dielectric layer, the replacement gate having lateral edges vertically aligned with lateral edges of the superlattice channel.

A semiconductor device comprising:

• a substrate;
• a pair of spaced apart isolation regions in said substrate;
• source and drain regions spaced apart in the substrate and between the pair of the isolation regions;
• the substrate having a channel recess extending between the source and drain regions;
• a superlattice channel in the channel recess and contacting the source and drain regions, the superlattice channel including a plurality of stacked groups of layers, each group of layers of the superlattice channel comprising a plurality of stacked base semiconductor monolayers defining a base semiconductor portion and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions;
• and
• a gate over the superlattice channel comprising a dielectric layer and a metal gate electrode thereon, the gate having lateral edges vertically aligned with lateral edges of the superlattice channel.