High-Isolation P-Substrate on RF PMOS

A memory device, comprising:

• a plurality of memory cells being formed over an active region that extends along a first lateral direction;
• a first interconnect structure operatively configured as a bit line and extending along the first lateral direction;
• a second interconnect structure operatively configured as a power rail carrying a ground voltage and extending along the first lateral direction;
• and
• a plurality of epitaxial structures formed in the active region and coupled to either the first interconnect structure or the second interconnect structure;
• wherein a first one of the plurality of epitaxial structures has a vertical sidewall in direct contact with a first dielectric structure, and wherein the vertical sidewall of the first epitaxial structure faces a second lateral direction perpendicular to the first lateral direction.

A method for forming memory devices, comprising:

• forming an active region extending along a first lateral direction;
• forming a plurality of gate structures over the active region, each of the gate structures extending along a second lateral direction perpendicular to the first lateral direction;
• forming a plurality of epitaxial structures in the active region, each of the gate structures interposed between adjacent ones of the epitaxial structures, wherein the active region, the gate structures, and the epitaxial structure operatively form a plurality of memory cells;
• replacing a first portion of a first one of the epitaxial structures with a first dielectric structure, wherein the first dielectric structure has a first width extending along the second lateral direction;
• and
• replacing a second portion of a second one of the epitaxial structures with a second dielectric structure, wherein the second dielectric structure has a second width extending along the second lateral direction, and wherein the second width is different from the first width.