Methods for making radio frequency (RF) semiconductor devices including a ground plane layer having a superlattice

A method for making a radio frequency (RF) semiconductor device comprising:

• forming an RF ground plane layer on a silicon-on-insulator (SOI) substrate by at least
• doping the silicon layer of the SOI substrate, and
• forming a superlattice on the doped silicon layer, the superlattice comprising a plurality of stacked groups of layers, each group of layers comprising a plurality of stacked base silicon monolayers defining a base silicon portion, and at least one oxygen monolayer constrained within a crystal lattice of adjacent base silicon portions;
• forming a body above the RF ground plane layer;
• forming spaced apart source and drain regions adjacent the body and defining a channel region in the body;
• and
• forming a gate overlying the channel region.

A method for making a radio frequency (RF) switch comprising:

• forming an RF ground plane layer on a semiconductor-on-insulator substrate by at least
• doping the semiconductor layer of the semiconductor-on-insulator substrate, and
• forming a superlattice on the doped semiconductor layer, the superlattice comprising a plurality of stacked groups of layers, each group of layers 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;
• forming a body above the RF ground plane layer;
• forming a body contact coupled to the body and the RF ground plane layer;
• forming spaced apart source and drain regions adjacent the body and defining a channel region in the body;
• and
• forming a gate overlying the channel region for controlling charge carrier flow through the channel region responsive to an RF switching control signal.